In this paper, the microstructure and hardness of Ti-5Al-2Sn-2Zr-4Mo-4Cr titanium alloy with and without laser shock peening (LSP) were examined and compared. The titanium alloy samples were laser shock peened with different layers at the same power density. The microscopic structure after LSP are tested and analyzed by SEM and TEM. The results indicated that LSP changed the microstructure evidently. After 3 layers laser shock peening, there are nanocrystallization in the LSP zone. The shock wave provided high strain rate deformation and generated high-density dislocations in the material. Multiple severe plastic deformation caused by 3 to 5 LSP layers helped to rearrange the resultant dislocation, to form dislocation networks, leading to the formation of nanocrystallites. On the other hand, the microhardness across the polished surfaces of the titanium materials with and without LSP was measured. It is obvious that the laser shock peening improved the microhardness of the Ti-5Al-2Sn-2Zr-4Mo-4Cr for about 16% at the surface, and the affected depth is about 300 microns from the surface.

The goal of this work was to determine effects of laser shock peening (LSP) on the fatigue life of the nickel-based superalloy, as well as the mechanism including the residual stress-depth profile (both depth of compression and magnitude) and the microstructure. The vibration fatigue performance of the standard test coupons made by Ni-based superalloy K417 with and without laser shock peening is researched. The residual stress distribution and microscopic structure after LSP are tested and analyzed by X-ray diffraction, SEM and TEM. The results indicated that the compress residual stress is up to 1.0mm in the test coupons after LSP, and the maximum residual compressive stress is about 660MPa under the surface. At the same time, the high pressure shock wave caused by laser propagate into the material which formed high density dislocation in the surface of the samples, and the γ' is divided leading to increase the sub-grain. Because of the deep residual compressive stress, high density dislocation and much more sub-grains, the vibration fatigue strength is improved about 180MPa by LSP. It is very instructive in the structure design and applying LSP to Ni-based superalloy.

In this paper, the microstructure and microhardness of laser shock processed (LSP) Ti-6Al-2.5Mo-1.5Cr-0.5Fe-0.3Si titanium alloy with and without annealing were examined and compared. The titanium alloy samples were LSP processed with 3 layers at 4.24GW/cm2. Some of the samples were vacuum annealed at 623K for 10 hours. The microscopic structure with and without annealing were tested and analyzed by SEM, TEM. The results indicated that after LSP, the shock wave provided high strain rate deformation and led to the formation of ultra-fine grain. Comparing with the samples without annealing, the dislocation density was lower and the grain-boundary was more distinct in the annealed samples, but the sizes of the ultra-fine grain didn’t grow bigger after annealing. On the other hand, the microhardness measurement was made on the cross-section. It is obviously that the laser shock processing improved the microhardness of the Ti-6Al-2.5Mo-1.5Cr-0.5Fe-0.3Si for about 12.2% at the surface, and the hardness affected depth is about 500 microns. The microhardness after annealing is 10 HV0.5lower, but the affected depth is not changed. The titanium alloy after LSP is thermostable at 623K; thus break the USA standard AMS2546, in which titanium parts after LSP are subjected in subsequent processing should not exceed 589K.

A new low-cost displacement sensing approach is put forward. It employs physical multiplication by using multiple linear encoders and differential grating codestrips, and the differential phase configuration is mechanically guaranteed; furthermore, a flash signal processing circuit comprising time sequence generator, counter and D/A with no microprocessors involved is also developed. Theoretical analysis is presented, and a test system using Heds-9730 as the detecting unit is built, and then experiments on an electromagnetic actuator are carried out. The measured results agreed well with the original, and the results prove that the sensing approach can achieve high sampling rate, high resolution and cost saving, thus providing an effective displacement measuring means for cost-sensitive applications.

In this paper, the microstructure and microhardness of Ti-6.5Al-3.5Mo-1.5Zr-0.3Si titanium alloy with and without laser shock peening (LSP) were examined and compared. The titanium alloy samples were treated with different layers, at the same power density. X-ray diffraction (XRD), Transmission Electron Microscope (TEM) and microhardness techniques were used to analyse microstructure and mechanical. X-ray diffraction analysis shows that there was not any phase transformation and no new crystalline phases have been formed. TEM studies demonstrate that both α and β phase can been refined in the surface layer with LSP. The microhardness measurements with LSP demonstrate that Hardness of crystallization surface is high up to 418MPa, which is more than the sample without LSP, the shock wave improved the microhardness for about 8%, and the affected depth is about 400 microns from the surface.