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Structural Investigations On Nanocrystalline Ni-W Alloy Films By Transmission Electron Microscopy
Structural Investigations On Nanocrystalline Ni-W Alloy Films By Transmission Electron Microscopy
A.S. Md Abdul Haseeb
Electrodeposited Ni-W alloys have been investigated in the as-deposited state by transmission electron microscopy in order to investigate the microstructural features in dependence of the tungsten content. Within the tungsten content range from 7 at.% up to 12 at.%, the microstructure is nanocrystalline characterized by a bimodal grain size distribution, consisting out of 20 to 200 nm sized grains and also larger grains with several 100 nm characteristic dimension. No clear trend in microstructure formation is visible with W content or deposition conditions in the investigated W content range. Only solid solution phase characteristics were observed. The lattice constant is …
Phase Change Mechanisms During Femtosecond Laser Pulse Train Ablation Of Nickel Thin Films, Xin Li, Lan Jiang, Hai-Lung Tsai
Phase Change Mechanisms During Femtosecond Laser Pulse Train Ablation Of Nickel Thin Films, Xin Li, Lan Jiang, Hai-Lung Tsai
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The mechanisms of nickel thin films irradiated by femtosecond laser pulse trains are studied by a model using molecular dynamics simulations and two-temperature model. It is found that the pulse train technology can change energy transport and corresponding phase change processes. Compared with single pulse ablation at the same total fluence, the pulse trains lead to (1) lower ablation rate with more and smaller uniform nanoparticles, (2) higher film surface temperatures and longer thermalization time, (3) much lower electron thermal conductivity that can further control heat-affected zone, (4) significantly smaller film compressive stresses and tensile stresses which reduce microcracks, and …