The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Stewart W Williams - One of the best experts on this subject based on the ideXlab platform.
-
microstructure hardness and mechanical properties of two different unalloyed tantalum wires deposited via wire arc Additive Manufacture
International Journal of Refractory Metals & Hard Materials, 2019Co-Authors: Gianrocco Marinelli, Filomeno Martina, Supriyo Ganguly, Stewart W WilliamsAbstract:Abstract An innovative way of producing large-scale unalloyed tantalum parts, based on the Wire + Arc Additive Manufacturing process, has been developed in this study. Two different unalloyed tantalum wires have been used to deposit 200-mm-long structures in tantalum. The effect of the wire chemistry on microstructure, hardness, porosity, mechanical properties and strain localisation has been investigated. The deposits showed high integrity and excellent mechanical properties, with yield strength, ultimate tensile strength and elongation as high as 234 MPa, 261 MPa, and 36%, respectively. Indeed, yield strength was higher than commercially available tantalum, even though, in this study, the grains were large and had a high aspect ratio. Wire + Arc Additive Manufacture has clearly shown the potential to produce tantalum components with relatively low cost and reduced lead time, thus offering a new robust and viable manufacturing route.
-
high cycle fatigue and fatigue crack growth rate in Additive Manufactured titanium alloys
30th Symposium of the International Committee on Aeronautical Fatigue ICAF 2019, 2019Co-Authors: Xiang Zhang, Filomeno Martina, J Ding, Abdul Khadar Syed, Romali Biswal, Stewart W WilliamsAbstract:The Wire + Arc Additive Manufacture (WAAM) process can produce large metal parts in the metre scale, at much higher deposition rate and more efficient material usage compared to the powder bed fusion Additive manufacturing (AM) processes. WAAM process also offers lead time reduction and much lower buy-to-fly ratio compared to traditional process methods, e.g. forgings. Research is much needed in the areas of fatigue and fracture performance for qualification and certification of Additive Manufactured aircraft components.
-
development of wire arc Additive Manufacture for the production of large scale unalloyed tungsten components
International Journal of Refractory Metals & Hard Materials, 2019Co-Authors: Gianrocco Marinelli, Filomeno Martina, Supriyo Ganguly, Stewart W WilliamsAbstract:Abstract The manufacturing of refractory-metals components presents some limitations induced by the materials' characteristic low-temperature brittleness and high susceptibility to oxidation. Powder metallurgy is typically the manufacturing process of choice. Recently, Wire + Arc Additive Manufacture has proven capable to produce fully-dense large-scale metal parts at relatively low cost, by using high-quality wire as feedstock. In this study, this technique has been used for the production of large-scale tungsten linear structures. The orientation of the wire feeding has been studied and optimised to obtain defect-free tungsten deposits. In particular, front wire feeding eliminated the occurrence of pores and micro-cracks, when compared to side wire feeding. The microstructure, the occurrence of defects and their relationship with the deposition process have also been discussed. Despite the repetitive thermal cycles and the inherent brittleness of the material, the as-deposited structures were free from internal cracks and the layer dimensions were stable during the entire deposition process. This enabled the production of a relatively large-scale component, with the dimension of 210 × 75 × 12 mm. This study has demonstrated that Wire + Arc Additive Manufacture can be used to produce large-scale parts in unalloyed tungsten by complete fusion, presenting a potential alternative to the powder metallurgy manufacturing route.
-
oxidation of ti 6al 4v during wire and arc Additive Manufacture
3D Printing and Additive Manufacturing, 2019Co-Authors: Armando Caballero, J Ding, Yashwanth K Bandari, Stewart W WilliamsAbstract:Abstract Owing to the high reactivity of titanium with oxygen at high temperatures, oxidation is often observed during wire and arc Additive Manufacture (WAAM) of Ti-6Al-4V. As a sign of oxidation,...
-
ultrasonic phased array inspection of wire arc Additive Manufacture samples using conventional and total focusing method imaging approaches
Insight, 2019Co-Authors: Yashar Javadi, J Ding, Stewart W Williams, Charles Macleod, S G Pierce, Anthony Gachagan, William J Kerr, Momchil Vasilev, Carmelo Mineo, Jerzy DziewierzAbstract:In this study, three aluminium samples produced by wire + arc Additive Manufacture (WAAM) are inspected using ultrasonic phased array technology. Artificial defects are machined using a centre drill, o3 mm, and electro-discharge machining (EDM), o0.5-1 mm, in a cylindrical through hole topology. The sample was first inspected by a single element wheel probe mounted on a KUKA robot in order to investigate the feasibility of using a conventional ultrasonic transducer approach. Unfortunately, the wheel probe was found to be unsuitable for scanning of the WAAM specimens and ultrasonic phased arrays were employed next. The setup included 5 MHz and 10 MHz arrays (128 elements) in direct contact with the sample surface using both conventional and total focusing method (TFM) imaging techniques. Using FIToolbox (Diagnostic Sonar, UK) as the controller, a phased array aperture of 32 elements was used to perform a focussed B-scan with a range of settings for the transmit focal depth. All the reflectors (including those located near the WAAM top surface) were successfully detected by a combination of conventional phased array and TFM, using a range of settings and setups including bottom surface inspection, application through a Plexiglas wedge and variation of the scanning frequency.
J Ding - One of the best experts on this subject based on the ideXlab platform.
-
Wire Laser Arc Additive Manufacture of aluminium zinc alloys
Welding in the World, 2020Co-Authors: E. Eimer, Stewart Williams, W. Suder, J DingAbstract:Aluminium zinc alloys are widely used in the aerospace industry due to their high strength. However, only a few studies have been reported on the Additive Manufacture of aluminium zinc alloys. This rarity is due to the difficulties occurring during the fusion processing of these alloys and to the lack of available raw material. This paper presents an alternative process used for the deposition of aluminium zinc alloys. In this study, a Wire Laser Arc Additive Manufacture (WLAAM) system was used. This consisted of a gas metal arc power source, used to generate the melt pool, and a laser beam applied to control the melt pool size. By using this approach, it was possible to produce an elongated melt pool and feed zinc into it with a cold wire without compromising the process stability. A welding camera along with a system measuring the arc voltage and current was used to monitor the process. Different process parameters and configurations were investigated along with their effect on process stability and deposited material microstructure. A very high zinc concentration was achieved in the deposited material without macro-segregation.
-
mechanical performance and microstructural characterisation of titanium alloy alloy composites built by wire arc Additive Manufacture
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2019Co-Authors: Alec Davis, Filomeno Martina, J Ding, Cameron I Breheny, Jonathan Fellowes, U Nwankpa, Thays Machry, Phil PrangnellAbstract:Abstract A first stage study has been performed to investigate the potential for exploiting high deposition rate WAAM to print dual-alloy microstructures. Samples were built using alternating feed wires of commercially-pure Ti and Ti–6Al–4V. A high level of dilution occurred during deposition accompanied by effective liquid-phase mixing, producing a regular distribution of solidified melt tracks of approximate bimodal composition each less extreme than that of their respective constituent feed wires. The yield strength of the dual alloy composite material was approximately midway between that of the two alloys from which it was produced and exhibited a double inflection yield behaviour. Overall, because of the relatively coarse length scale there was not a significant property advantage in tensile loading above that of a chemically homogenous material, thus the main advantage of printing alternate alloys at this length scale is likely to reside more with increasing crack path tortuosity during fracture or fatigue loading. Importantly, the deposited material was found to have a refined β-grain structure suggesting that the composition gradients introduced by dual-alloy printing can disrupt the epitaxial columnar growth normally seen in WAAM deposits.
-
high cycle fatigue and fatigue crack growth rate in Additive Manufactured titanium alloys
30th Symposium of the International Committee on Aeronautical Fatigue ICAF 2019, 2019Co-Authors: Xiang Zhang, Filomeno Martina, J Ding, Abdul Khadar Syed, Romali Biswal, Stewart W WilliamsAbstract:The Wire + Arc Additive Manufacture (WAAM) process can produce large metal parts in the metre scale, at much higher deposition rate and more efficient material usage compared to the powder bed fusion Additive manufacturing (AM) processes. WAAM process also offers lead time reduction and much lower buy-to-fly ratio compared to traditional process methods, e.g. forgings. Research is much needed in the areas of fatigue and fracture performance for qualification and certification of Additive Manufactured aircraft components.
-
oxidation of ti 6al 4v during wire and arc Additive Manufacture
3D Printing and Additive Manufacturing, 2019Co-Authors: Armando Caballero, J Ding, Yashwanth K Bandari, Stewart W WilliamsAbstract:Abstract Owing to the high reactivity of titanium with oxygen at high temperatures, oxidation is often observed during wire and arc Additive Manufacture (WAAM) of Ti-6Al-4V. As a sign of oxidation,...
-
ultrasonic phased array inspection of wire arc Additive Manufacture samples using conventional and total focusing method imaging approaches
Insight, 2019Co-Authors: Yashar Javadi, J Ding, Stewart W Williams, Charles Macleod, S G Pierce, Anthony Gachagan, William J Kerr, Momchil Vasilev, Carmelo Mineo, Jerzy DziewierzAbstract:In this study, three aluminium samples produced by wire + arc Additive Manufacture (WAAM) are inspected using ultrasonic phased array technology. Artificial defects are machined using a centre drill, o3 mm, and electro-discharge machining (EDM), o0.5-1 mm, in a cylindrical through hole topology. The sample was first inspected by a single element wheel probe mounted on a KUKA robot in order to investigate the feasibility of using a conventional ultrasonic transducer approach. Unfortunately, the wheel probe was found to be unsuitable for scanning of the WAAM specimens and ultrasonic phased arrays were employed next. The setup included 5 MHz and 10 MHz arrays (128 elements) in direct contact with the sample surface using both conventional and total focusing method (TFM) imaging techniques. Using FIToolbox (Diagnostic Sonar, UK) as the controller, a phased array aperture of 32 elements was used to perform a focussed B-scan with a range of settings for the transmit focal depth. All the reflectors (including those located near the WAAM top surface) were successfully detected by a combination of conventional phased array and TFM, using a range of settings and setups including bottom surface inspection, application through a Plexiglas wedge and variation of the scanning frequency.
Supriyo Ganguly - One of the best experts on this subject based on the ideXlab platform.
-
microstructure hardness and mechanical properties of two different unalloyed tantalum wires deposited via wire arc Additive Manufacture
International Journal of Refractory Metals & Hard Materials, 2019Co-Authors: Gianrocco Marinelli, Filomeno Martina, Supriyo Ganguly, Stewart W WilliamsAbstract:Abstract An innovative way of producing large-scale unalloyed tantalum parts, based on the Wire + Arc Additive Manufacturing process, has been developed in this study. Two different unalloyed tantalum wires have been used to deposit 200-mm-long structures in tantalum. The effect of the wire chemistry on microstructure, hardness, porosity, mechanical properties and strain localisation has been investigated. The deposits showed high integrity and excellent mechanical properties, with yield strength, ultimate tensile strength and elongation as high as 234 MPa, 261 MPa, and 36%, respectively. Indeed, yield strength was higher than commercially available tantalum, even though, in this study, the grains were large and had a high aspect ratio. Wire + Arc Additive Manufacture has clearly shown the potential to produce tantalum components with relatively low cost and reduced lead time, thus offering a new robust and viable manufacturing route.
-
development of wire arc Additive Manufacture for the production of large scale unalloyed tungsten components
International Journal of Refractory Metals & Hard Materials, 2019Co-Authors: Gianrocco Marinelli, Filomeno Martina, Supriyo Ganguly, Stewart W WilliamsAbstract:Abstract The manufacturing of refractory-metals components presents some limitations induced by the materials' characteristic low-temperature brittleness and high susceptibility to oxidation. Powder metallurgy is typically the manufacturing process of choice. Recently, Wire + Arc Additive Manufacture has proven capable to produce fully-dense large-scale metal parts at relatively low cost, by using high-quality wire as feedstock. In this study, this technique has been used for the production of large-scale tungsten linear structures. The orientation of the wire feeding has been studied and optimised to obtain defect-free tungsten deposits. In particular, front wire feeding eliminated the occurrence of pores and micro-cracks, when compared to side wire feeding. The microstructure, the occurrence of defects and their relationship with the deposition process have also been discussed. Despite the repetitive thermal cycles and the inherent brittleness of the material, the as-deposited structures were free from internal cracks and the layer dimensions were stable during the entire deposition process. This enabled the production of a relatively large-scale component, with the dimension of 210 × 75 × 12 mm. This study has demonstrated that Wire + Arc Additive Manufacture can be used to produce large-scale parts in unalloyed tungsten by complete fusion, presenting a potential alternative to the powder metallurgy manufacturing route.
-
investigation of process factors affecting mechanical properties of inconel 718 superalloy in wire arc Additive Manufacture process
Journal of Materials Processing Technology, 2019Co-Authors: J Ding, Supriyo Ganguly, Stewart W WilliamsAbstract:Abstract This paper systematically evaluated the effect of oxide, wire source and heat treatment on the mechanical properties of wire + arc Additively Manufactured (WAAM) INCONEL 718. Comparison of the as deposited grain structure was made with laser-powder based AM and wrought INCONEL 718. Results showed that oxides formed during deposition had no effect on the mechanical properties since a 0.5μm thick passivation layer consisting of Cr2O3 and Al2O3 formed upon deposition and prevented further oxides from forming inside the bulk. Wires from different suppliers resulted in around 50 MPa difference in UTS possibly due to the slight compositional variation and uncertainties in TiN inclusion. Standard heat treatment improved the strength from 824 MPa to 1110 MPa in the horizontal direction, but the average strength was 105 MPa lower than the wrought alloy. The as deposited WAAM INCONEL718 featured large columnar grains and numerous Laves phase, as compared to the fine grains of laser powder bed fusion and wrought INCONEL 718. This starting microstructure led to less favourable and less numerous precipitates forming during heat treatment, which is the main reason for the strength mismatch. A different heat treatment would not help due to the starting microstructure.
-
preliminary investigation of building strategies of maraging steel bulk material using wire arc Additive Manufacture
Journal of Materials Engineering and Performance, 2019Co-Authors: J Ding, Chenglei Diao, Supriyo Ganguly, S.w. WilliamsAbstract:Wire + arc Additive Manufacture (WAAM) is a new process for fabricating large-scale metallic components. In this paper, the use of cold metal transfer-based WAAM process for the production of maraging steel bulk material is reported. Process parameters were studied, and the effect of building strategies including oscillation, parallel and weaving on bead shape was investigated. The structural integrity of the WAAM bulk material regarding the surface finish, lack-of-fusion issue and microstructure was characterized. Results proved the feasibility of applying WAAM to producing maraging steel bulk material, and weaving was identified to be most recommended building strategy.
-
wire arc Additive Manufacture of 17 4 ph stainless steel effect of different processing conditions on microstructure hardness and tensile strength
Journal of Materials Processing Technology, 2019Co-Authors: Armando Caballero, J Ding, Supriyo Ganguly, Stewart W WilliamsAbstract:Abstract Wire + Arc Additive Manufacture (WAAM) is receiving increasing attention as it offers a way to fabricate meter scale parts, with relatively low capital cost, lower material wastage and logistical advantages. A wide range of metallic alloys could be Manufactured using this process. Martensitic grade precipitation-hardening stainless steel 17-4 PH offers excellent combination of high strength and corrosion resistance. Hence, it is important to investigate the behaviour of this alloy in WAAM. In the present work, the effect of different process variables such as shielding gas, deposition path and post-fabrication heat treatment, on microstructure and mechanical properties were studied. A number of specimens were Manufactured by WAAM using the Fronius Cold Metal Transfer (CMT) process under different controlled processing conditions. These specimens were subsequently characterized by optical and electron microscopy and mechanical properties in terms of tensile strength and hardness. It was found that using shielding gases that result in higher heat input reduces the amount of retained austenite in the as-deposited microstructure. It has been demonstrated that the required tensile properties can be achieved by applying post-deposition heat treatment. However, it is suggested that direct aging in as deposited condition resulted in formation of harmful intermetallic phases which embrittles the deposit.
Filomeno Martina - One of the best experts on this subject based on the ideXlab platform.
-
microstructure hardness and mechanical properties of two different unalloyed tantalum wires deposited via wire arc Additive Manufacture
International Journal of Refractory Metals & Hard Materials, 2019Co-Authors: Gianrocco Marinelli, Filomeno Martina, Supriyo Ganguly, Stewart W WilliamsAbstract:Abstract An innovative way of producing large-scale unalloyed tantalum parts, based on the Wire + Arc Additive Manufacturing process, has been developed in this study. Two different unalloyed tantalum wires have been used to deposit 200-mm-long structures in tantalum. The effect of the wire chemistry on microstructure, hardness, porosity, mechanical properties and strain localisation has been investigated. The deposits showed high integrity and excellent mechanical properties, with yield strength, ultimate tensile strength and elongation as high as 234 MPa, 261 MPa, and 36%, respectively. Indeed, yield strength was higher than commercially available tantalum, even though, in this study, the grains were large and had a high aspect ratio. Wire + Arc Additive Manufacture has clearly shown the potential to produce tantalum components with relatively low cost and reduced lead time, thus offering a new robust and viable manufacturing route.
-
mechanical performance and microstructural characterisation of titanium alloy alloy composites built by wire arc Additive Manufacture
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2019Co-Authors: Alec Davis, Filomeno Martina, J Ding, Cameron I Breheny, Jonathan Fellowes, U Nwankpa, Thays Machry, Phil PrangnellAbstract:Abstract A first stage study has been performed to investigate the potential for exploiting high deposition rate WAAM to print dual-alloy microstructures. Samples were built using alternating feed wires of commercially-pure Ti and Ti–6Al–4V. A high level of dilution occurred during deposition accompanied by effective liquid-phase mixing, producing a regular distribution of solidified melt tracks of approximate bimodal composition each less extreme than that of their respective constituent feed wires. The yield strength of the dual alloy composite material was approximately midway between that of the two alloys from which it was produced and exhibited a double inflection yield behaviour. Overall, because of the relatively coarse length scale there was not a significant property advantage in tensile loading above that of a chemically homogenous material, thus the main advantage of printing alternate alloys at this length scale is likely to reside more with increasing crack path tortuosity during fracture or fatigue loading. Importantly, the deposited material was found to have a refined β-grain structure suggesting that the composition gradients introduced by dual-alloy printing can disrupt the epitaxial columnar growth normally seen in WAAM deposits.
-
high cycle fatigue and fatigue crack growth rate in Additive Manufactured titanium alloys
30th Symposium of the International Committee on Aeronautical Fatigue ICAF 2019, 2019Co-Authors: Xiang Zhang, Filomeno Martina, J Ding, Abdul Khadar Syed, Romali Biswal, Stewart W WilliamsAbstract:The Wire + Arc Additive Manufacture (WAAM) process can produce large metal parts in the metre scale, at much higher deposition rate and more efficient material usage compared to the powder bed fusion Additive manufacturing (AM) processes. WAAM process also offers lead time reduction and much lower buy-to-fly ratio compared to traditional process methods, e.g. forgings. Research is much needed in the areas of fatigue and fracture performance for qualification and certification of Additive Manufactured aircraft components.
-
development of wire arc Additive Manufacture for the production of large scale unalloyed tungsten components
International Journal of Refractory Metals & Hard Materials, 2019Co-Authors: Gianrocco Marinelli, Filomeno Martina, Supriyo Ganguly, Stewart W WilliamsAbstract:Abstract The manufacturing of refractory-metals components presents some limitations induced by the materials' characteristic low-temperature brittleness and high susceptibility to oxidation. Powder metallurgy is typically the manufacturing process of choice. Recently, Wire + Arc Additive Manufacture has proven capable to produce fully-dense large-scale metal parts at relatively low cost, by using high-quality wire as feedstock. In this study, this technique has been used for the production of large-scale tungsten linear structures. The orientation of the wire feeding has been studied and optimised to obtain defect-free tungsten deposits. In particular, front wire feeding eliminated the occurrence of pores and micro-cracks, when compared to side wire feeding. The microstructure, the occurrence of defects and their relationship with the deposition process have also been discussed. Despite the repetitive thermal cycles and the inherent brittleness of the material, the as-deposited structures were free from internal cracks and the layer dimensions were stable during the entire deposition process. This enabled the production of a relatively large-scale component, with the dimension of 210 × 75 × 12 mm. This study has demonstrated that Wire + Arc Additive Manufacture can be used to produce large-scale parts in unalloyed tungsten by complete fusion, presenting a potential alternative to the powder metallurgy manufacturing route.
-
microstructural evolution and mechanical properties of maraging steel produced by wire arc Additive Manufacture process
Materials Characterization, 2017Co-Authors: Xiangfang Xu, J Ding, Supriyo Ganguly, Stewart W Williams, Filomeno MartinaAbstract:Abstract Wire + arc Additive Manufacture is developed for producing large-scale metallic components. In this paper, maraging steel parts were produced, and the microstructure and mechanical properties were investigated. The microhardness and tensile strength of the as deposited alloy reduced from the bottom to the top due to the transient thermal cycling, which resulted in partial aging and non-uniform formation of intermetallic compounds along the building direction. Solutionizing, followed by 3 h aging, significantly reduced the microstructural heterogeneity and increased the mechanical properties by 24.7% through the formation of large amounts of finely distributed precipitates. The as deposited alloy possessed superior strength to the wrought alloy in solutionized condition but inferior to the later in aged condition, which was attributed to the less pronounced aging response of the low-angle columnar grains characterized microstructure and the presence of retained and reverted austenite.
Adam T. Clare - One of the best experts on this subject based on the ideXlab platform.
-
Targeted rework strategies for powder bed Additive Manufacture
Additive Manufacturing, 2018Co-Authors: S. Catchpole-smith, P. Dryburgh, Matthias Hirsch, L. Parry, Steve D Sharples, M Hirsch, Ian A. Ashcroft, R Patel, Adam T. ClareAbstract:A major factor limiting the adoption of powder-bed-fusion Additive manufacturing for production of parts is the control of build process defects and the effect these have upon the certification of parts for structural applications. In response to this, new methods for detecting defects and to monitor process performance are being developed. However, effective utilisation of such methods to rework parts in process has yet to be demonstrated. This study investigates the use of spatially resolved acoustic spectroscopy (SRAS) scan data to inform repair strategies within a commercial selective laser melting machine. New methodologies which allow for rework of the most common defects observed in selective laser melting (SLM) manufacturing are proposed and demonstrated. Three rework methodologies are applied to targeted surface breaking pores: a hatch pattern, a spiral pattern and a single shot exposure. The work presented shows that it is possible to correct surface breaking pores using targeted re-melting, reducing the depth of defects whilst minimising changes in local texture. For the hatch rework and spiral rework, a reduction in defect depth of 50% and 31% were observed, respectively, however, no improvement was seen after the single shot exposures. This work is part of a programme to develop a method by which defects can be detected and the part reworked in-process during SLM to enable defect specification targets to be met. Although further work in developing build-characterise-rework strategies for integrated and targeted defect correction is needed, the feasibility of the underlying method of identifying and selectively reworking to reduce a defect has now been demonstrated for the first time.
-
microstructure and mechanical properties of ti 2al alloyed with mo formed in laser Additive Manufacture
Journal of Alloys and Compounds, 2017Co-Authors: Adam T. Clare, Xin Lin, Fengying Zhang, Meng Yang, Hua Tan, Yongnan ChenAbstract:Abstract A series of Ti-2Al- y Mo ( y = 2,5,7,9,12) alloy samples were produced from blended elemental Ti, Al and Mo powders using the laser solid forming technology. The influence of the β stabilizer Mo on the morphology of the grains, the size and the distribution of the α laths, the Vickers hardness and the tensile properties of Ti-2Al- y Mo alloys were explored under designated laser processing parameters. It was found that the microstructure in Ti-2Al-5Mo, Ti-2Al-7Mo, Ti-2Al-9Mo, and Ti-2Al-12Mo deposited layers were composed of irregular columnar grains that grow epitaxially, with some small equiaxed grains in the upper region, while that of the Ti-2Al-2Mo alloy was composed of large columnar grains. The grain size decreased, while the thickness of equiaxed grains layer increased with increasing Mo content. This indicates a tendency towards columnar-to-equiaxed transition with increasing Mo. The dominant β grains form a basketweave microstructure composed of primary α laths, secondary α laths and retained β phase. It was also observed that with increasing Mo content, both the size of primary α laths and secondary α laths decreased significantly, while the number of secondary α laths increased sharply, and the Ti-2Al-12Mo is also constituted of α phase and β phase. The Young's modulus of Ti-2Al-7Mo, Ti-2Al-9Mo, and Ti-2Al-12Mo were basically the same within experimental error. Tensile testing of the specimens showed that Ti-2Al-7Mo exhibits a good combination of strength and elongation to failure. As a result, this material can be considered suitable as a viable feedstock for laser Additive manufacturing.
-
Assessing the capability of in-situ nondestructive analysis during layer based Additive Manufacture
Additive Manufacturing, 2017Co-Authors: Guangying Guan, Matthias Hirsch, Rikesh Patel, Steve D Sharples, Adam T. Clare, Richard K. Leach, Wenqi LiAbstract:Unlike more established subtractive or constant volume manufacturing technologies, Additive manufacturing methods suffer from a lack of in-situ monitoring methodologies which can provide information relating to process performance and the formation of defects. In-process evaluation for Additive manufacturing is becoming increasingly important in order to assure the integrity of parts produced in this way. This paper addresses the generic performance of inspection methods suitable for Additive manufacturing. Key process and measurement parameters are explored and the impacts these have upon production rates are defined. Essential working parameters are highlighted, within which the spatial opportunity and temporal penalty for measurement allow for comparison of the suitability of different nondestructive evaluation techniques. A new method of benchmarking in-situ inspection instruments and characterising their suitability for Additive manufacturing processes is presented to act as a design tool to accommodate end user requirements. Two inspection examples are presented: spatially resolved acoustic spectroscopy and optical coherence tomography for scanning selective laser melting and selective laser sintering parts, respectively. Observations made from the analyses presented show that the spatial capability arising from scanning parameters affects the temporal penalty and hence impact upon production rates. A case study, created from simulated data, has been used to outline the spatial performance of a generic nondestructive evaluation method and to show how a decrease in data capture resolution reduces the accuracy of measurement.