The Experts below are selected from a list of 14127 Experts worldwide ranked by ideXlab platform
Takayuki Takasugi - One of the best experts on this subject based on the ideXlab platform.
-
effects of combined plasma carburizing and shot peening on fatigue and wear properties of ti 6al 4v alloy
Surface & Coatings Technology, 2009Co-Authors: N Tsuji, S Tanaka, Takayuki TakasugiAbstract:Abstract The effects of combined plasma-carburizing and shot-peening on fatigue and wear properties of Ti–6Al–4V alloy specimen were investigated. Surface morphology and roughness, microstructure, Compressive Residual Stress, work hardening state, and micro-hardness on the surface modified layer in the Ti–6Al–4V alloy specimen were measured and analyzed. The shot-peening effectively induces highly Compressive Residual Stress and work hardening states on the surface layer of the plasma-carburized Ti–6Al–4V alloy specimen. Consequently, the fatigue life of plasma-carburized Ti–6Al–4V alloy specimen has been significantly improved by subsequent shot-peening. The cracks of both shot-peened and shot-peened carburized specimens initiated on the surface at higher applied Stress levels. On the contrary, interior-originating fractures occurred at lower applied Stress levels. Corresponding to this behavior, the S – N curves show the shape of two-step stages. The wear resistance of Ti–6Al–4V alloy specimen was also significantly improved by the hardness increase on the surface layer by combination of plasma-carburizing and shot-peening.
-
effect of combined plasma carburizing and deep rolling on notch fatigue property of ti 6al 4v alloy
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2009Co-Authors: N Tsuji, S Tanaka, Takayuki TakasugiAbstract:This paper discusses the effects of a combination of plasma-carburizing and deep-rolling on notch fatigue properties of a Ti-6Al-4V alloy. Circumferentially V-notched cylindrical Ti-6Al-4V alloy specimens were plasma-carburized at a relatively low temperature for the improvement of wear resistance, and then, deep-rolled at the notch root for inducing Compressive Residual Stress. Scanning electron microscopy, optical microscopy, laser scanning microscopy, surface roughness tester, and micro-hardness tester were used to characterize the modified surface layer at the notch root. Axial loading fatigue tests (R = 0.1) were performed using a servo-hydraulic testing machine in a laboratory atmosphere at an ambient temperature. The notch fatigue life of the specimen was reduced by plasma-carburizing due to the brittleness caused by the higher hardness in addition to the disappearance of Compressive Residual Stress on the notched surface, but remarkably improved by the subsequent deep-rolling. The surface layer containing the Compressive Residual Stress and the work hardening induced by deep-rolling effectively prevented and delayed the fatigue crack initiation and propagation of deep-rolled carburized specimen.
-
evaluation of surface modified ti 6al 4v alloy by combination of plasma carburizing and deep rolling
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2008Co-Authors: N Tsuji, S Tanaka, Takayuki TakasugiAbstract:Abstract Plasma surface diffusion processes such as plasma-carburizing and nitriding have been used to improve tribological properties of titanium and its alloys. However, the improvement of fatigue strength by these processes has not been successful due to brittleness introduced in the high-hardness surface layer and the disappearance of Compressive Residual Stress and grain growth by heating. In this work, a Ti–6Al–4V alloy sample was plasma-carburized at a relatively low temperature to improve wear resistance, and then, deep-rolled to induce Compressive Residual Stress. Scanning electron microscopy, optical microscopy, laser scanning microscopy, surface roughness tester, X-ray diffractometer, and micro-hardness tester were used to characterize the modified surface layer. The Residual Stress and work hardening state was analyzed by X-ray diffraction techniques. The effect of deep-rolling on fatigue strength and wear resistance of plasma-carburized Ti–6Al–4V alloy was also investigated. The fatigue properties and wear resistance of Ti–6Al–4V alloy modified by a combination of low-temperature plasma-carburizing and deep-rolling were significantly improved in comparison with those of the unmodified Ti–6Al–4V alloy.
N Tsuji - One of the best experts on this subject based on the ideXlab platform.
-
effects of combined plasma carburizing and shot peening on fatigue and wear properties of ti 6al 4v alloy
Surface & Coatings Technology, 2009Co-Authors: N Tsuji, S Tanaka, Takayuki TakasugiAbstract:Abstract The effects of combined plasma-carburizing and shot-peening on fatigue and wear properties of Ti–6Al–4V alloy specimen were investigated. Surface morphology and roughness, microstructure, Compressive Residual Stress, work hardening state, and micro-hardness on the surface modified layer in the Ti–6Al–4V alloy specimen were measured and analyzed. The shot-peening effectively induces highly Compressive Residual Stress and work hardening states on the surface layer of the plasma-carburized Ti–6Al–4V alloy specimen. Consequently, the fatigue life of plasma-carburized Ti–6Al–4V alloy specimen has been significantly improved by subsequent shot-peening. The cracks of both shot-peened and shot-peened carburized specimens initiated on the surface at higher applied Stress levels. On the contrary, interior-originating fractures occurred at lower applied Stress levels. Corresponding to this behavior, the S – N curves show the shape of two-step stages. The wear resistance of Ti–6Al–4V alloy specimen was also significantly improved by the hardness increase on the surface layer by combination of plasma-carburizing and shot-peening.
-
effect of combined plasma carburizing and deep rolling on notch fatigue property of ti 6al 4v alloy
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2009Co-Authors: N Tsuji, S Tanaka, Takayuki TakasugiAbstract:This paper discusses the effects of a combination of plasma-carburizing and deep-rolling on notch fatigue properties of a Ti-6Al-4V alloy. Circumferentially V-notched cylindrical Ti-6Al-4V alloy specimens were plasma-carburized at a relatively low temperature for the improvement of wear resistance, and then, deep-rolled at the notch root for inducing Compressive Residual Stress. Scanning electron microscopy, optical microscopy, laser scanning microscopy, surface roughness tester, and micro-hardness tester were used to characterize the modified surface layer at the notch root. Axial loading fatigue tests (R = 0.1) were performed using a servo-hydraulic testing machine in a laboratory atmosphere at an ambient temperature. The notch fatigue life of the specimen was reduced by plasma-carburizing due to the brittleness caused by the higher hardness in addition to the disappearance of Compressive Residual Stress on the notched surface, but remarkably improved by the subsequent deep-rolling. The surface layer containing the Compressive Residual Stress and the work hardening induced by deep-rolling effectively prevented and delayed the fatigue crack initiation and propagation of deep-rolled carburized specimen.
-
evaluation of surface modified ti 6al 4v alloy by combination of plasma carburizing and deep rolling
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2008Co-Authors: N Tsuji, S Tanaka, Takayuki TakasugiAbstract:Abstract Plasma surface diffusion processes such as plasma-carburizing and nitriding have been used to improve tribological properties of titanium and its alloys. However, the improvement of fatigue strength by these processes has not been successful due to brittleness introduced in the high-hardness surface layer and the disappearance of Compressive Residual Stress and grain growth by heating. In this work, a Ti–6Al–4V alloy sample was plasma-carburized at a relatively low temperature to improve wear resistance, and then, deep-rolled to induce Compressive Residual Stress. Scanning electron microscopy, optical microscopy, laser scanning microscopy, surface roughness tester, X-ray diffractometer, and micro-hardness tester were used to characterize the modified surface layer. The Residual Stress and work hardening state was analyzed by X-ray diffraction techniques. The effect of deep-rolling on fatigue strength and wear resistance of plasma-carburized Ti–6Al–4V alloy was also investigated. The fatigue properties and wear resistance of Ti–6Al–4V alloy modified by a combination of low-temperature plasma-carburizing and deep-rolling were significantly improved in comparison with those of the unmodified Ti–6Al–4V alloy.
Hitoshi Soyama - One of the best experts on this subject based on the ideXlab platform.
-
Use of an Abrasive Water Cavitating Jet and Peening Process to Improve the Fatigue Strength of Titanium Alloy 6Al-4V Manufactured by the Electron Beam Powder Bed Melting (EBPB) Additive Manufacturing Method
JOM, 2019Co-Authors: Hitoshi Soyama, Daniel SandersAbstract:Metal components made by additive manufacturing have large inherent surface roughness, and, as such, their strength and fatigue life can be reduced significantly versus wrought products. In order to improve these properties, a novel mechanical surface treatment that introduces Compressive Residual Stress while simultaneously reducing the surface roughness is proposed. The proposed treatment uses cavitation peening combined with an abrasive slurry. The impact of the kinetic energy-charged abrasive particles, induced by collapsing water cavitation vapor bubbles, produces Compressive Residual Stress, while the abrasive reduces the surface roughness. Plane-bending fatigue tests were carried out to determine the effectiveness of this treatment on the fatigue life and strength of titanium alloy Ti6Al4V manufactured by electron beam melting. It was demonstrated that the fatigue strength of an as-built specimen was improved from 169 MPa to 280 MPa by the proposed treatment.
-
The Use of Cavitation Peening to Increase the Fatigue Strength of Duralumin Plates Containing Fastener Holes
Materials Sciences and Applications, 2014Co-Authors: Hitoshi SoyamaAbstract:An effective method for improving the fatigue life of Duralumin plates with fastener holes, such as those used in the construction of aircraft, is to introduce a Compressive Residual Stress around the fastener holes. Cavitation peening is a novel peening method that uses the cavitation impact produced when a high-speed water jet is injected into a water-filled chamber. In this paper, Duralumin plate specimens with holes were treated by cavitation peening under various conditions, and the fatigue strength of the specimens was determined using a plate bending fatigue test. It was revealed that a Compressive Residual Stress was introduced not only on surfaces perpendicular to the axis of the cavitating jet but also on the walls of holes which were parallel to this. It was found that a 51% improvement in fatigue strength could be achieved by cavitation peening. Note that this is first report demonstrating an improvement in the fatigue life of Duralumin plates with fastener holes by cavitation peening.
-
numerical simulation of the effects of Residual Stress on the concentration of hydrogen around a crack tip
Surface & Coatings Technology, 2012Co-Authors: Osamu Takakuwa, Masaaki Nishikawa, Hitoshi SoyamaAbstract:Abstract For this study we used finite element analysis to show how the Residual Stress affects the hydrogen concentration around a crack tip in a plastically deformable material after a fatigue process. Following a 9 cycle fatigue process, hydrogen diffusion analysis was carried out at the highest applied fatigue Stress. This showed hydrogen invading the crack surface and diffusing into the material. The concentration of hydrogen was higher close to the crack tip and its behavior was largely affected by the Residual Stress in the material. Tensile Residual Stress accelerated the hydrogen invasion and increased its concentration, while Compressive Residual Stress simulated as the Stress induced by peening clearly suppressed them. This is due to the affect the Residual Stress has on the hydrostatic Stress around the crack tip which is a dominant factor in the hydrogen diffusion behavior. Peening, which is a surface treatment used to introduce Compressive Residual Stress to enhance the mechanical properties of a material, such as its resistance to Stress corrosion cracking and its fatigue strength, may, therefore, suppress the embrittlement caused by hydrogen.
-
relieving micro strain by introducing macro strain in a polycrystalline metal surface by cavitation shotless peening
Materials Letters, 2008Co-Authors: Hitoshi Soyama, N. YamadaAbstract:Abstract Peening using cavitation impact is called “cavitation shotless peening CSP”, since there is no requirement for shot in the process. Micro- and macro-strain of polycrystalline metal peened by CSP were evaluated using X-ray diffraction methods, as the full width at half maximum (FWHM) of the X-ray diffraction profile from the peened surface was decreased, although Compressive Residual Stress was introduced. It was found that CSP reduced the micro-strain in the surface, but simultaneously introduced Compressive Residual Stress, i.e., a macro-strain. The results demonstrate that the micro-strain is relieved by CSP without the need for heat treatment, and is, therefore, a sort of annealing. Thus, CSP can renew the metallic material while the shape itself is maintained.
-
introduction of Compressive Residual Stress using a cavitating jet in air
Journal of Engineering Materials and Technology-transactions of The Asme, 2004Co-Authors: Hitoshi SoyamaAbstract:Cavitation impact from a cavitation jet, which is formed from bubbles induced by a high-speed water jet in water, can be used for surface modification in a similar manner to shot peening. A cavitating jet is normally produced by injecting a high-speed water jet into a water-filled chamber. It is possible to make a cavitating jet in air by injecting a high-speed water jet into a concentric low-speed water jet that surrounds the high-speed jet. In order to demonstrate this, a high-speed water jet with a concentric low-speed water jet was impacted onto an aluminum specimen to observe the pattern of erosion. The mass loss of the specimen was weighed to measure the capability of the jet, since a more powerful jet produces a larger mass loss. It was shown that the combination of high- and concentric low-speed water jets produced a typical erosion pattern such as that obtained using a cavitating jet in a water-filled chamber. When the injection pressure of the concentric low-speed water jet was optimised, the capability of the cavitating jet in air was much greater than that of a cavitating jet in a water-filled chamber. It was demonstrated that an optimized cavitating jet in air introduced more Compressive Residual Stress in the surface of tool steel alloy than that from a cavitating jet in a water-filled chamber. In addition, this Stress was larger than that induced by shot peening. The peened surface was also less rough compared with shot peening.
Chuanhai Jiang - One of the best experts on this subject based on the ideXlab platform.
-
surface mechanical property and Residual Stress of peened nickel aluminum bronze determined by in situ x ray diffraction
Applied Surface Science, 2017Co-Authors: Chengxi Wang, Yuantao Zhao, Chuanhai Jiang, Ming Chen, Vincent JiAbstract:Abstract As one of the most important surface strengthening method, shot peening is widely used to improve the fatigue and Stress corrosion crack resistance of components by introducing the refined microstructure and Compressive Residual Stress in the surface layer. However, the mechanical properties of this thin layer are different from the base metal and are difficult to be characterized by conventional techniques. In this work, a micro uniaxial tensile tester equipped with in-situ X-ray Stress analyzer was employed to make it achievable on a nickel-aluminum bronze with shot peening treatment. According to the equivalent Stress-strain relationship based on Von Mises Stress criterion, the Young’s modulus and yield strength of the peened layer were calculated. The results showed that the Young’s modulus was the same as the bulk material, and the yield strength corresponding to the permanent plastic strain of 0.2% was increased by 21% after SP. But the fractographic analysis showed that the fracture feature of the surface layer was likely to transform from the dimple to the cleavage, indicating the improved strength might be attained at the expense of ductility. The monotonic and cyclic loading were also performed via the same combined set-up. In addition, the specific relaxation behavior of Compressive Residual Stress was quantified by linear logarithm relationship between Residual Stress and cycle numbers. It was found that the Compressive Residual Stress mainly relaxed in the first few cycles, and then reached steady state with further cycles. The relaxation rate and the stable value were chiefly depended on the Stress amplitude and number of cycles. The retained Residual Stress kept in Compressive under all given applied Stress levels, suggesting that the shot peening could introduce a more stable surface layer of Compressive Residual Stress other than the elevated strength of nickel-aluminum bronze alloy.
-
micro structure and surface layer properties of 18crnimo7 6 steel after multistep shot peening
Materials & Design, 2013Co-Authors: Peng Fu, K Zhan, Chuanhai JiangAbstract:Abstract The effects of multistep shot peening on the structure and mechanical properties of 18CrNiMo7-6 steel have been investigated using X-ray diffraction line profile analysis. X-ray diffraction data reveals the phase transformation from austenite to martensitic phase after SP treatments. The results show that multistep shot peening can more significantly improve the mechanical properties. The optimal peening intensity of 0.50 + 0.30 + 0.15 mmA is found for 18CrNiMo7-6 steel. With the optimized shot peening treatment, the maximum Compressive Residual Stress (located at the depth of 20 μm for martensite) and top-surface Compressive Residual Stress of martensite attain the values of 1463 and 1256 MPa, respectively; While those of austenite are 1039 and 766 MPa, respectively. The domain size of 18CrNiMo7-6 steel decreases to 11.1 nm on the top surface after shot peening with the intensity of 0.50 + 0.30 + 0.15 mmA, and the micro-hardness on the top surface attains the peak value of 1175 HV.
-
uniformity of Residual Stress distribution on the surface of s30432 austenitic stainless steel by different shot peening processes
Materials Letters, 2013Co-Authors: K Zhan, Chuanhai Jiang, Vincent JiAbstract:Abstract Compressive Residual Stress induced by shot peening can effectively improve the fatigue resistance of the treated component. Much attention has been paid to increase the Compressive Residual Stress value, and the uniformity of Residual Stress distribution was often ignored, which was also very important for improving the fatigue resistance. In this paper, the uniformity of Compressive Residual Stress distributions on the surface of S30432 austenitic stainless steel after three different shot peening treatments has been investigated by X-ray diffraction method. The results revealed that compared with traditional shot peening, multi-step shot peening (dual shot peening, triple shot peening) methods can not only increase the Stress value but also make the Stress distribution more uniform.
-
effect of preStress state on surface layer characteristic of s30432 austenitic stainless steel in shot peening process
Materials & Design, 2012Co-Authors: K Zhan, Chuanhai JiangAbstract:Residual Stress and microstructure on surface deformed layer of S30432 austenitic stainless steel after shot peening with different preStress states were investigated. The domain size and micro-strain in the deformed layer were analyzed by Voigt method. The results showed that the Compressive Residual Stress and microstructure were improved significantly after Stress shot peening. The values of Compressive Residual Stress depended on both the preStress state and the measurement directions. Microstructure investigations revealed that smaller domain size and higher micro-strain were induced compared with the conventional shot peening. And the variations of microstructure were mainly influenced by the values of preStress state. Based on these investigations, it is concluded that Stress shot peening is superior to conventional shot peening and it is an effective method to improve the surface properties of S30432 austenitic stainless steel.
-
Residual Stress relaxation of shot peened deformation surface layer on s30432 austenite steel under applied loading
Materials Transactions, 2012Co-Authors: K Zhan, Chuanhai JiangAbstract:The relaxation of Residual Stress in shot peened surface layer on S30432 austenite steel under static and cyclic loading was investigated. The results revealed that the Compressive Residual Stresses were relaxed under applied tensile Stress. The relaxation of Residual Stresses in longitudinal direction was more obvious than that in transverse direction. And when applied Stress was beyond the yield strength of the materials, the relaxation of the Compressive Residual Stress was drastic. Under cyclic loading, the results showed that the relaxation behavior was determined by the applied loading and the number of cycles. And the fast relaxation of the Compressive Residual Stress took place in the first few cycles then became stable gradually. Finally, a model was used to quantitatively predict the Compressive Residual Stress under cyclic loading with different applied tensile Stresses. [doi:10.2320/matertrans.M2012111]
Weidong Zhao - One of the best experts on this subject based on the ideXlab platform.
-
the effect of ultrasonic surface rolling process on the fretting fatigue property of gh4169 superalloy
International Journal of Fatigue, 2020Co-Authors: Jing Yang, Daoxin Liu, Xiaohua Zhang, Mingxia Liu, Weidong Zhao, Chengsong LiuAbstract:Abstract To improve the fretting fatigue (FF) resistance of GH4169 superalloy, ultrasonic surface rolling process (USRP) is carried once and three times on material surface and the effect of surface integrity on FF is investigated. The results show that USRP significantly reduces the surface roughness of GH4169 superalloy and improves surface micro-hardness as well as induces a high intensity Compressive Residual Stress at deep thickness. The dislocation density beneath the top surface is increased and the grains of the material surface are refined. A gradient nanostructured layer is observed beneath the surface and the equiaxed nanograins are generated with the size of around 37.6 nm at the top surface of USRP-3 sample. The FF test indicates the FF life of GH4169 superalloy increase by 3.6 times and 11 times, by one and three USRP treatments, respectively. In addition, the factor separation test indicates that the Compressive Residual Stress plays an important role in improving the FF life of GH4169 superalloy.
-
effect of the ultrasonic surface rolling process on the fretting fatigue behavior of ti 6al 4v alloy
Materials, 2017Co-Authors: Chengsong Liu, Daoxin Liu, Xiaohua Zhang, Weidong ZhaoAbstract:The effect of the ultrasonic surface rolling process (USRP) on the rotary bending fretting fatigue (FF) of Ti-6Al-4V alloy was investigated. The reason for the USRP’s ability to improve the FF resistance of Ti-6Al-4V alloy was studied. The results revealed that the USRP induced a Compressive Residual Stress field with a depth of 530 μm and a maximum Residual Stress of −930 MPa. Moreover, the surface micro-hardness of the USRP sample was significantly higher than that of the untreated base material (BM) sample, and the USRP yielded a 72.7% increase in the FF limit of the alloy. These further enhanced fatigue properties contributed mainly to the Compressive Residual Stress field with large numerical value and deep distribution, which could effectively suppress FF crack initiation and early propagation. The USRP-induced surface work-hardening had only a minor impact on the FF resistance.