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Full-Text Articles in Mechanical Engineering
Controlled Nanocrystallization Of Niti Shape Memory Alloy By Laser Shock Peening, Chang Ye, Gary Cheng
Controlled Nanocrystallization Of Niti Shape Memory Alloy By Laser Shock Peening, Chang Ye, Gary Cheng
Dr. Chang Ye
In this paper, partial amorphization of NiTi alloys by laser shock peening (LSP) is reported. The microstructure of NiTi after LSP was characterized by transmission electron microscopy (TEM). The amorphization mechanism was discussed in light of the high strain rate deformation characteristics of LSP. With subsequent controlled annealing after LSP, nanostructure with different grain size distribution was achieved.
Fatigue Performance Improvement By Dynamic Strain Aging And Dynamic Precipitation In Warm Laser Shock Peening Of Aisi 4140 Steel, Chang Ye, Gary Cheng
Fatigue Performance Improvement By Dynamic Strain Aging And Dynamic Precipitation In Warm Laser Shock Peening Of Aisi 4140 Steel, Chang Ye, Gary Cheng
Dr. Chang Ye
Warm laser shock peening (WLSP) integrates the advantages of laser shock peening and thermal-mechanical treatment (TMT) to improve material fatigue performance. Compared to traditional laser shock peening (LSP), warm laser shock peening, i.e. LSP at elevated temperature, leads to better performance in many aspects. WLSP can induce nanoscale precipitations by dynamic precipitation and high density dislocation by dynamic strain aging (DSA), resulting in higher surface strength, which is beneficial for fatigue life improvement. Due to pinning of dislocation structure by nanoscale precipitates, and the pinning of dislocation structure by Cottrell atmosphere, or the DSA effect, stability of the dislocation arrangement …
Nucleation Of Highly Dense Nanoscale Precipitates Based On An Innovative Process: Warm Laser Shock Peening, Yiliang Liao, Chang Ye, Gary Cheng
Nucleation Of Highly Dense Nanoscale Precipitates Based On An Innovative Process: Warm Laser Shock Peening, Yiliang Liao, Chang Ye, Gary Cheng
Dr. Chang Ye
Warm laser shock peening (WLSP) is an innovative thermo-mechanical processing technique, which combines the advantages of laser shock peening (LSP) and dynamic aging (DA). It has been found that a unique microstructure with highly dense nanoscale precipitates surrounded by dense dislocation structures is generated by WLSP. In order to understand the nucleation mechanism of the highly dense precipitates during WLSP, aluminum alloy 6061 (AA6061) has been used by investigating the WLSP process with experiments and analytical modeling. An analytical model has been proposed to estimate the nucleation rate in metallic materials after WLSP. The effects of the processing temperature and …
Numerical Simulation On Nanoparticles Integrated Laser Shock Peening Of Aluminum Alloy, Chang Ye, Gary Cheng
Numerical Simulation On Nanoparticles Integrated Laser Shock Peening Of Aluminum Alloy, Chang Ye, Gary Cheng
Dr. Chang Ye
In this paper, numerical simulation of nanoparticle integrated laser shock peening of aluminum alloys was carried out. A “tied constraint” was used to connect the matrix and nanoparticle assembly in ABAQUS package. Different particle size and particle volumes fraction (PVF) were studied. It was found that there is significant stress concentration around the nanoparticles. The existence of nanoparticle will influence the stress wave propagation and thus the final stress and strain state of the material after LSP. In addition, particle size, PVF and particle orientation all influence the strain rate, static residual stress, static plastic strain and energy absorption during …