The Experts below are selected from a list of 1254 Experts worldwide ranked by ideXlab platform
Houxiao Wang - One of the best experts on this subject based on the ideXlab platform.
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laser drilling in Nickel Super Alloy sheets with and without ultrasonic assistance characterized by transient in process detection with indirect characterization after hole drilling
Optics and Laser Technology, 2021Co-Authors: Kaibo Xia, Houxiao Wang, Naifei Ren, Xudong Ren, Dan Liu, Chunhui Shi, Jianan TianAbstract:Abstract The water-based ultrasonic-assisted laser drilling has been recently reported for improving hole-drilling quality and efficiency, but its material removal mechanism is currently still not well understood. In this work, the high-speed photography was used for studying the transient laser drilling processes with and without water-based ultrasonic vibrations. The effects of camera shooting angle, laser pulse energy, assist gas pressure and ultrasonic vibrations on laser drilling processes were investigated and compared systematically. The influential mechanism of water-based ultrasonic assistance on transient material removal for laser drilling was first reported using high-speed camera observation with indirect characterization after hole-drilling. It was found that the melt ejection with spattering and the vapor-plasma plume expulsion from a drilling hole were enhanced by using ultrasonic vibrations without assist gas blowing. When a hole was through, more ejection and spattering signals were detected above the hole entrance due to the combined effect of water-based ultrasonic vibrations and water-induced “closed state” for the hole exit. The increase of the ultrasonic power enhanced hole-drilling and material removal amount, which was useful for drilling through a hole. The through-hole entrance and exit diameters increased with the ultrasonic power.
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Water-based helical laser hole-cutting in Nickel Super-Alloy GH4049 assisted by longitudinal and transverse magnetic fields with/without ultrasonic assistance
Optics and Lasers in Engineering, 2020Co-Authors: Houxiao Wang, Wei Zhou, Sukai Zhu, Frank ZibnerAbstract:Abstract A novel helical laser hole-cutting (HLHC) technology based on coupled assistance of water-based ultrasonic vibrations and external longitudinal/transverse magnetic fields is reported for cutting holes in Nickel Super-Alloy GH4049 sheets. Effects of external unidirectional transverse and longitudinal magnetic fields on HLHC performance were correspondingly analyzed and compared with and without water-based ultrasonic assistance. The influence of the loading direction of an external magnetic field and the magnetic field intensity of an external longitudinal/transverse magnetic field on HLHC performance is first reported based on systematic corresponding comparisons with and without water-based ultrasonic assistance. The effects of external longitudinal/transverse magnetic fields and beam expanding ratios on actual laser focal spot sizes were analyzed and discussed. It was demonstrated that the latest reported HLHC technology assisted by water-based ultrasonic vibrations and external longitudinal magnetic fields could generate deeper holes with relatively high cutting efficiency, smaller hole taper, higher hole aspect ratio, smaller hole circularity deviation, better hole wall quality, much better performance for relieving residual stress, thinner recast layer, more uniform refinement of grains, and better performance for improving micro hardness. Generally, a stronger external longitudinal magnetic field coupled by water-based ultrasonic vibrations was more helpful for cutting deeper and higher-quality holes. It was shown that the change of loading direction of an external magnetic field with/without ultrasonic assistance did not greatly alter recast layer formation and micro hardness performance for the workpiece helically cut. Compared to the transverse magnetic assistance, a corresponding longitudinal magnetic field coupled with water-based ultrasonic vibrations was more effective for micro hardness improvement for this reported HLHC technology. When using the same water-based ultrasonic vibration assistance, a stronger longitudinal magnetic field was more effective for relieving residual stress for the workpiece helically cut (a stress reduction percentage of around 96.5% was reported in this work). The average laser focal spot size obviously decreased with laser beam expanding ratio, but the external longitudinal/transverse magnetic assistance did not greatly alter the actual laser focal spot size.
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effect of water based ultrasonic vibration on the quality of laser trepanned microholes in Nickel Super Alloy workpieces
Journal of Materials Processing Technology, 2019Co-Authors: Houxiao Wang, Sukai Zhu, Naifei RenAbstract:Abstract Effusion cooling holes are commonly drilled in Nickel Super-Alloy aero-engine components using electro-discharge machining (EDM) or pulsed laser drilling. While drilling quality of EDM is high, its machining efficiency is normally relatively low, in addition to its high tooling cost. The drilling efficiency of a millisecond pulsed laser is much higher, while a recast layer often forms on the hole wall. In this paper, an ultrasonic-assisted laser trepanning technology is reported for trepanning blind and through holes in Nickel Super-Alloy samples. The influence of ultrasonic vibrations on hole geometry, morphology, microstructure, recast layer thickness and mechanical performance was investigated through comparing holes trepanned with and without ultrasonic assistance. It was found that ultrasonic vibrations contributed to laser trepanning process mainly by means of grain refinement strengthening, hard phase precipitation and dispersion strengthening, and led to recast layer reduction and negative taper for the through hole trepanned. The percentage of the measured recast layer reduction induced by ultrasonic vibrations approximately ranged from 15.73% to 31.82%. Besides, a maximum percentage of around 19.43% was achieved for micro hardness improvement induced by ultrasonic vibrations. However, the width of laser trepanned heat affected zone (HAZ) was increased by around 36.00% due to ultrasonic vibration assistance. In addition, the HAZ grains near the recast layer was refined via increasing the trepanning speed, decreasing pulse width. Compared with the base metal, the impact toughness was increased by using ultrasonic-enhanced laser trepanning mainly due to grain refinement strengthening.
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Comparison of percussion laser drilling quality with and without water-based ultrasonic assistance
Journal of Manufacturing Processes, 2018Co-Authors: Houxiao Wang, Guoxiang Xu, Wei ZhouAbstract:Abstract A millisecond-pulsed percussion laser drilling technique using water-based ultrasonic assistance is reported for drilling Nickel Super-Alloy GH4037 sheets with 12-mm-thickness. Influence of ultrasonic vibration on drilling quality including hole taper angle, hole sidewall quality, recast layer microstructure, and hardness distribution of hole heat affected zone (HAZ) is analyzed through comparing holes drilled without ultrasonic assistance. Recast layer reduction, grain refinement, and HAZ hardness increase induced by ultrasonic assistance are also analyzed. It is shown that ultrasonic vibration improves percussion laser drilling quality by reducing hole taper angle, cleaning hole sidewall, decreasing hole defects, reducing recast layer thickness, refining grains, decreasing hole sidewall surface roughness, and increasing micro hardness.
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Primary exploration on water-based magnetic-ultrasonic assisted laser drilling/trepanning technique
Sixth International Conference on Optical and Photonic Engineering (icOPEN 2018), 2018Co-Authors: Houxiao Wang, Guoxiang Xu, Anand Asundi, Tao Song, Ye XuAbstract:Electro-discharge machining (EDM) and pulsed laser drilling/trepanning are commonly used for fabricating cooling holes. Although the EDM technique produces high quality holes, it is very slow, without mentioning the high tooling cost. The millisecond pulsed laser drilling/trepanning is much faster. However, a laser with millisecond pulses usually cannot drill/trepan high quality microholes, mainly resulting from the normally encountered recast layer formation with metallurgical/morphological defects. In this study, a water-based magnetic-assisted ultrasonic-enhanced laser drilling/trepanning technique is accordingly reported for drilling and trepanning microholes with and without ultrasonic/magnetic assistance, improving laser drilling and trepanning performance. This novel technique was primarily explored through experimental characterization and numerical analysis, including the ultrasonic-enhanced laser trepanning of Nickel Super-Alloy sheets, magnetic-assisted ultrasonic-enhanced percussion laser drilling of Nickel SuperAlloy sheets, and numerical analysis for ultrasonic-enhanced laser trepanning of stainless steel sheets. Effects of ultrasonic/magnetic assistance on millisecond pulsed Nd:YAG laser drilling/trepanning performance and quality are reported through comparing the drilled/trepanned holes without and using ultrasonic/magnetic assistance. Numerical analysis was also carried out for simulating the fields of temperature and residual stress resulting from laser drilling/trepanning with and without ultrasonic assistance.
Naifei Ren - One of the best experts on this subject based on the ideXlab platform.
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laser drilling in Nickel Super Alloy sheets with and without ultrasonic assistance characterized by transient in process detection with indirect characterization after hole drilling
Optics and Laser Technology, 2021Co-Authors: Kaibo Xia, Houxiao Wang, Naifei Ren, Xudong Ren, Dan Liu, Chunhui Shi, Jianan TianAbstract:Abstract The water-based ultrasonic-assisted laser drilling has been recently reported for improving hole-drilling quality and efficiency, but its material removal mechanism is currently still not well understood. In this work, the high-speed photography was used for studying the transient laser drilling processes with and without water-based ultrasonic vibrations. The effects of camera shooting angle, laser pulse energy, assist gas pressure and ultrasonic vibrations on laser drilling processes were investigated and compared systematically. The influential mechanism of water-based ultrasonic assistance on transient material removal for laser drilling was first reported using high-speed camera observation with indirect characterization after hole-drilling. It was found that the melt ejection with spattering and the vapor-plasma plume expulsion from a drilling hole were enhanced by using ultrasonic vibrations without assist gas blowing. When a hole was through, more ejection and spattering signals were detected above the hole entrance due to the combined effect of water-based ultrasonic vibrations and water-induced “closed state” for the hole exit. The increase of the ultrasonic power enhanced hole-drilling and material removal amount, which was useful for drilling through a hole. The through-hole entrance and exit diameters increased with the ultrasonic power.
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effect of water based ultrasonic vibration on the quality of laser trepanned microholes in Nickel Super Alloy workpieces
Journal of Materials Processing Technology, 2019Co-Authors: Houxiao Wang, Sukai Zhu, Naifei RenAbstract:Abstract Effusion cooling holes are commonly drilled in Nickel Super-Alloy aero-engine components using electro-discharge machining (EDM) or pulsed laser drilling. While drilling quality of EDM is high, its machining efficiency is normally relatively low, in addition to its high tooling cost. The drilling efficiency of a millisecond pulsed laser is much higher, while a recast layer often forms on the hole wall. In this paper, an ultrasonic-assisted laser trepanning technology is reported for trepanning blind and through holes in Nickel Super-Alloy samples. The influence of ultrasonic vibrations on hole geometry, morphology, microstructure, recast layer thickness and mechanical performance was investigated through comparing holes trepanned with and without ultrasonic assistance. It was found that ultrasonic vibrations contributed to laser trepanning process mainly by means of grain refinement strengthening, hard phase precipitation and dispersion strengthening, and led to recast layer reduction and negative taper for the through hole trepanned. The percentage of the measured recast layer reduction induced by ultrasonic vibrations approximately ranged from 15.73% to 31.82%. Besides, a maximum percentage of around 19.43% was achieved for micro hardness improvement induced by ultrasonic vibrations. However, the width of laser trepanned heat affected zone (HAZ) was increased by around 36.00% due to ultrasonic vibration assistance. In addition, the HAZ grains near the recast layer was refined via increasing the trepanning speed, decreasing pulse width. Compared with the base metal, the impact toughness was increased by using ultrasonic-enhanced laser trepanning mainly due to grain refinement strengthening.
Sukai Zhu - One of the best experts on this subject based on the ideXlab platform.
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Water-based helical laser hole-cutting in Nickel Super-Alloy GH4049 assisted by longitudinal and transverse magnetic fields with/without ultrasonic assistance
Optics and Lasers in Engineering, 2020Co-Authors: Houxiao Wang, Wei Zhou, Sukai Zhu, Frank ZibnerAbstract:Abstract A novel helical laser hole-cutting (HLHC) technology based on coupled assistance of water-based ultrasonic vibrations and external longitudinal/transverse magnetic fields is reported for cutting holes in Nickel Super-Alloy GH4049 sheets. Effects of external unidirectional transverse and longitudinal magnetic fields on HLHC performance were correspondingly analyzed and compared with and without water-based ultrasonic assistance. The influence of the loading direction of an external magnetic field and the magnetic field intensity of an external longitudinal/transverse magnetic field on HLHC performance is first reported based on systematic corresponding comparisons with and without water-based ultrasonic assistance. The effects of external longitudinal/transverse magnetic fields and beam expanding ratios on actual laser focal spot sizes were analyzed and discussed. It was demonstrated that the latest reported HLHC technology assisted by water-based ultrasonic vibrations and external longitudinal magnetic fields could generate deeper holes with relatively high cutting efficiency, smaller hole taper, higher hole aspect ratio, smaller hole circularity deviation, better hole wall quality, much better performance for relieving residual stress, thinner recast layer, more uniform refinement of grains, and better performance for improving micro hardness. Generally, a stronger external longitudinal magnetic field coupled by water-based ultrasonic vibrations was more helpful for cutting deeper and higher-quality holes. It was shown that the change of loading direction of an external magnetic field with/without ultrasonic assistance did not greatly alter recast layer formation and micro hardness performance for the workpiece helically cut. Compared to the transverse magnetic assistance, a corresponding longitudinal magnetic field coupled with water-based ultrasonic vibrations was more effective for micro hardness improvement for this reported HLHC technology. When using the same water-based ultrasonic vibration assistance, a stronger longitudinal magnetic field was more effective for relieving residual stress for the workpiece helically cut (a stress reduction percentage of around 96.5% was reported in this work). The average laser focal spot size obviously decreased with laser beam expanding ratio, but the external longitudinal/transverse magnetic assistance did not greatly alter the actual laser focal spot size.
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effect of water based ultrasonic vibration on the quality of laser trepanned microholes in Nickel Super Alloy workpieces
Journal of Materials Processing Technology, 2019Co-Authors: Houxiao Wang, Sukai Zhu, Naifei RenAbstract:Abstract Effusion cooling holes are commonly drilled in Nickel Super-Alloy aero-engine components using electro-discharge machining (EDM) or pulsed laser drilling. While drilling quality of EDM is high, its machining efficiency is normally relatively low, in addition to its high tooling cost. The drilling efficiency of a millisecond pulsed laser is much higher, while a recast layer often forms on the hole wall. In this paper, an ultrasonic-assisted laser trepanning technology is reported for trepanning blind and through holes in Nickel Super-Alloy samples. The influence of ultrasonic vibrations on hole geometry, morphology, microstructure, recast layer thickness and mechanical performance was investigated through comparing holes trepanned with and without ultrasonic assistance. It was found that ultrasonic vibrations contributed to laser trepanning process mainly by means of grain refinement strengthening, hard phase precipitation and dispersion strengthening, and led to recast layer reduction and negative taper for the through hole trepanned. The percentage of the measured recast layer reduction induced by ultrasonic vibrations approximately ranged from 15.73% to 31.82%. Besides, a maximum percentage of around 19.43% was achieved for micro hardness improvement induced by ultrasonic vibrations. However, the width of laser trepanned heat affected zone (HAZ) was increased by around 36.00% due to ultrasonic vibration assistance. In addition, the HAZ grains near the recast layer was refined via increasing the trepanning speed, decreasing pulse width. Compared with the base metal, the impact toughness was increased by using ultrasonic-enhanced laser trepanning mainly due to grain refinement strengthening.
Adrian Leyland - One of the best experts on this subject based on the ideXlab platform.
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Thermal cyclic performance of NiAl/alumina-stabilized zirconia thermal barrier coatings deposited using a hybrid arc and magnetron sputtering system
Surface and Coatings Technology, 2006Co-Authors: K.j. Huang, J.t. Chang, A. Davison, K.c. Chen, Chiao-chi Lin, Allan Matthews, Adrian LeylandAbstract:In the present work, a hybrid arc/sputter deposition system is used to deposit alumina-stabilized zirconia (ASZ) thermal barrier coatings. An initial NiAl bond coat is deposited on the Nickel Super Alloy substrates, in the same coating system, by arc ion plating alone. The as-deposited ASZ coatings have a dense columnar structure. From X-ray diffractometry (XRD), it is found that the as-deposited ASZ films are almost entirely tetragonal. This is believed to result from the relatively high concentration of aluminum (10 at.%) in the ASZ films. Thermal testing is carried out over numerous cycles, each consisting of 30 and 10 min at 1100 °C and ambient, respectively. During thermal testing, a significant amount of the tetragonal phase is transformed to monoclinic. Furthermore a significant number of cracks, both parallel and perpendicular to the substrate surface, are found to occur in the ASZ layer as a result of tensile and compressive thermal stresses. Although a thermally grown oxide (TGO) layer between the top and bond coat, and Kirkendall voids in the interfacial region between substrate and bond coat occur in this coating system, the failure occurs principally as a result of parallel cracks which form just above the TGO. After 200 thermal cycles, a great portion of the topcoat has failed. The formation of cracks, and the subsequent coating failure, is likely to result from the dense coatings being unable to accommodate the thermal stresses parallel to the surface during the cycling tests.
Wei Zhou - One of the best experts on this subject based on the ideXlab platform.
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Water-based helical laser hole-cutting in Nickel Super-Alloy GH4049 assisted by longitudinal and transverse magnetic fields with/without ultrasonic assistance
Optics and Lasers in Engineering, 2020Co-Authors: Houxiao Wang, Wei Zhou, Sukai Zhu, Frank ZibnerAbstract:Abstract A novel helical laser hole-cutting (HLHC) technology based on coupled assistance of water-based ultrasonic vibrations and external longitudinal/transverse magnetic fields is reported for cutting holes in Nickel Super-Alloy GH4049 sheets. Effects of external unidirectional transverse and longitudinal magnetic fields on HLHC performance were correspondingly analyzed and compared with and without water-based ultrasonic assistance. The influence of the loading direction of an external magnetic field and the magnetic field intensity of an external longitudinal/transverse magnetic field on HLHC performance is first reported based on systematic corresponding comparisons with and without water-based ultrasonic assistance. The effects of external longitudinal/transverse magnetic fields and beam expanding ratios on actual laser focal spot sizes were analyzed and discussed. It was demonstrated that the latest reported HLHC technology assisted by water-based ultrasonic vibrations and external longitudinal magnetic fields could generate deeper holes with relatively high cutting efficiency, smaller hole taper, higher hole aspect ratio, smaller hole circularity deviation, better hole wall quality, much better performance for relieving residual stress, thinner recast layer, more uniform refinement of grains, and better performance for improving micro hardness. Generally, a stronger external longitudinal magnetic field coupled by water-based ultrasonic vibrations was more helpful for cutting deeper and higher-quality holes. It was shown that the change of loading direction of an external magnetic field with/without ultrasonic assistance did not greatly alter recast layer formation and micro hardness performance for the workpiece helically cut. Compared to the transverse magnetic assistance, a corresponding longitudinal magnetic field coupled with water-based ultrasonic vibrations was more effective for micro hardness improvement for this reported HLHC technology. When using the same water-based ultrasonic vibration assistance, a stronger longitudinal magnetic field was more effective for relieving residual stress for the workpiece helically cut (a stress reduction percentage of around 96.5% was reported in this work). The average laser focal spot size obviously decreased with laser beam expanding ratio, but the external longitudinal/transverse magnetic assistance did not greatly alter the actual laser focal spot size.
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Comparison of percussion laser drilling quality with and without water-based ultrasonic assistance
Journal of Manufacturing Processes, 2018Co-Authors: Houxiao Wang, Guoxiang Xu, Wei ZhouAbstract:Abstract A millisecond-pulsed percussion laser drilling technique using water-based ultrasonic assistance is reported for drilling Nickel Super-Alloy GH4037 sheets with 12-mm-thickness. Influence of ultrasonic vibration on drilling quality including hole taper angle, hole sidewall quality, recast layer microstructure, and hardness distribution of hole heat affected zone (HAZ) is analyzed through comparing holes drilled without ultrasonic assistance. Recast layer reduction, grain refinement, and HAZ hardness increase induced by ultrasonic assistance are also analyzed. It is shown that ultrasonic vibration improves percussion laser drilling quality by reducing hole taper angle, cleaning hole sidewall, decreasing hole defects, reducing recast layer thickness, refining grains, decreasing hole sidewall surface roughness, and increasing micro hardness.