Effect of Laser Peening on Residual Stress and Micro-Hardness of TC4 Titanium Alloy

2013 ◽  
Vol 710 ◽  
pp. 208-212
Author(s):  
Hong Chao Qiao ◽  
Ji Bin Zhao ◽  
Yi Xiang Zhao ◽  
Lun Li
Keyword(s):  
Residual Stress ◽  
Titanium Alloy ◽  
Layer Thickness ◽  
Pulse Energy ◽  
Work Piece ◽  
Laser Peening ◽  
Micro Hardness ◽  
X Ray Diffraction ◽  
Hardness Tester ◽  
Tc4 Titanium Alloy

Laser peening offers potential advantages over conventional peen technologies in terms of the depth of the residual stresses that can be induced, and improvements in surface micro-hardness. The present study was undertaken to understand the effect of laser penning on the properties of titanium alloy, a TC4 titanium alloy work-piece was processed with ND: YAG laser with the wavelength of 1064 nm, pulse energy of 0-10J and pulse width of 12ns, and micro-hardness and residual stress for different laser peening parameters were examined and analyzed by micro-hardness tester and X-ray diffraction. Results are presented and discussed of the residual stress profiles and the micro-hardness profiles, The experimental results show that the satisfying laser peening appearance can be achieved when the pulse energy was 6J, water tamping layer thickness was 1.8mm and ablative layer thickness was 100μm, surface micro-hardness increased by up to 33% and the compressive residual stress on the surface of laser shocked area reached up to-327.8MPa, laser peening improved hardness and residual stress of titanium alloy significantly. The experiment results show that the effect of laser peening was evidently.

Effect of Laser Peening on Residual Stress and Micro-Hardness of TC4 Titanium Alloy

2013 ◽  
Vol 341-342 ◽  
pp. 246-250
Author(s):  
Hong Chao Qiao ◽  
Ji Bin Zhao ◽  
Yi Xiang Zhao ◽  
Lun Li
Keyword(s):  
Residual Stress ◽  
Titanium Alloy ◽  
Layer Thickness ◽  
Pulse Energy ◽  
Work Piece ◽  
Laser Peening ◽  
Micro Hardness ◽  
X Ray Diffraction ◽  
Hardness Tester ◽  
Tc4 Titanium Alloy

Laser peening offers potential advantages over conventional peen technologies in terms of the depth of the residual stresses that can be induced, and improvements in surface micro-hardness. The present study was undertaken to understand the effect of laser penning on the properties of titanium alloy, a TC4 titanium alloy work-piece was processed with ND: YAG laser with the wavelength of 1064 nm, pulse energy of 0-10J and pulse width of 12ns, and micro-hardness and residual stress for different laser peening parameters were examined and analyzed by micro-hardness tester and X-ray diffraction. Results are presented and discussed of the residual stress profiles and the micro-hardness profiles, The experimental results show that the satisfying laser peening appearance can be achieved when the pulse energy was 6J, water tamping layer thickness was 1.8mm and ablative layer thickness was 100μm, surface micro-hardness increased by up to 33% and the compressive residual stress on the surface of laser shocked area reached up to-327.8MPa, laser peening improved hardness and residual stress of titanium alloy significantly. The experiment results show that the effect of laser peening was evidently.

scholarly journals Investigations into the Improvement of the Mechanical Properties of Ti-5Al-4Mo-4Cr-2Sn-2Zr Titanium Alloy by Using Low Energy Laser Peening without Coating

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1398
Author(s):  
Dingyuan Xue ◽  
Yang Jiao ◽  
Weifeng He ◽  
Xiaojun Shen ◽  
Yangjun Gao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Titanium Alloy ◽  
Fatigue Strength ◽  
Dynamic Equilibrium ◽  
Laser Energy ◽  
Strengthening Mechanism ◽  
Laser Peening ◽  
Micro Hardness ◽  
Laser Peening Without Coating

Mechanical properties, such as residual stress, micro-hardness and fatigue performance, of the Ti-5Al-4Mo-4Cr-2Sn-2Zr titanium alloy were improved via the laser peening without coating (LPwC) with a water-penetrable wavelength of 532 nm and pulse duration of 10 ns. In this paper, three kinds of laser energy, namely 85, 110 and 160 mJ were used to process the samples. The titanium alloy samples were also peened with different impact times (1, 3 or 5 impacts) at the energy of 85 mJ. The micro-hardness and residual stress distribution results provided that LPwC can introduce compressive residual stress (CRS) and also induce hardening of the target materials. Further, micro-hardness and CRS showed the increasing trends when the laser impact times increased. However, the CRS and micro-hardness decreased while the laser energy increased from 110 to 160 mJ, which was attributed to the dynamic equilibrium between the thermal and mechanical effects of LPwC. High cycle fatigue strength of the titanium alloy was significantly improved from 360 to 490.3 MPa after three impacts LPwC. The strengthening mechanism of fatigue strength subjected to LPwC was a combined effect between the laser-induced CRS and the high-density dislocations.

WC-Co Tool Failure Analysis and the Grinding Effect Study

2010 ◽  
Vol 139-141 ◽  
pp. 269-273 ◽  
Author(s):  
Xiu Xu Zhao
Keyword(s):  
Residual Stress ◽  
Effect Study ◽  
Work Piece ◽  
Grinding Process ◽  
X Ray Diffraction ◽  
Machining Processes ◽  
Tool Failure ◽  
Micro Cracks ◽  
Comparison Results ◽  
Grinding Conditions

Grinding is one of the important machining processes for the WC-Co carbide product. Different grinding strategies will have different impact on the work piece material. This study focuses on the WC-Co carbide grinding process, and the effect of grinding condition on the WC-Co carbide microstructure, figures out the relationship between different grinding strategies and material microstructure which relate to the WC-Co carbide tool failure. A specific microstructure analysis with Scanning Electric Microscope (SEM) will be presented based on a series of grinding experiments. The residual stress that generated in the grinding process will also be discussed based on the X-Ray Diffraction (XRD) measurements. It has been found that micro cracks are generated at certain grinding conditions with certain level. The residual stress which generated in the grinding process can be calculated by the d-spacing shift, and the comparison results show micro-cracks level is corresponding with the peaks shift in XRD test.

The Effects of Machined Workpiece Surface Integrity on the Fatigue Life of TC21 Titanium Alloy

2012 ◽  
Vol 503-504 ◽  
pp. 382-389 ◽  
Author(s):  
Dong Xing Du ◽  
Dao Xin Liu ◽  
Yu Feng Sun ◽  
Jin Gang Tang ◽  
Xiao Hua Zhang
Keyword(s):  
Residual Stress ◽  
Titanium Alloy ◽  
Fatigue Life ◽  
Surface Integrity ◽  
Surface Profile ◽  
Fatigue Properties ◽  
Profile Measurement ◽  
Micro Hardness ◽  
Finish Turning ◽  
Rough Turning

In this paper, the influence of different machining methods (including rough turning, finish turning, and longitudinal polishing after finish turning) on rotating bending fatigue properties of TC21 which belonged to a new ultra high strength titanium alloy was studied. The influence of machining methods on surface integrity of TC21 titanium alloy was measured by using surface profile measurement, scanning electron microscopy, metallography microscope, micro-hardness instrument and X-ray diffraction residual stress analyzer. And fatigue fractography of specimens was further investigated. Then the mechanism of fatigue resistance which was affected by machining surface integrity was discussed. The results indicated that the fatigue life of finish turning and longitudinal polishing after finish turning was increased 3.96 times and 17.34 times compared with rough turning, respectively. The machining surface integrity had important influence on fatigue property of TC21 titanium alloy, which caused by the differences of surface roughness and texture as the dominant factors, and then the variation in surface micro-hardness, metallographic microstructure and the surface residual stress were not the main factors on three above-mentioned machining methods. By using longitudinal polishing after finish turning processing method for preparation of TC21 titanium alloy parts could ensure good surface integrity and excellent fatigue performance.

Laser Shock Processing of Titanium Alloy Blade and FEM Simulation

2013 ◽  
Vol 456 ◽  
pp. 125-128
Author(s):  
Bing Yan ◽  
Rui Wang
Keyword(s):  
Residual Stress ◽  
Titanium Alloy ◽  
Residual Stresses ◽  
Fem Simulation ◽  
Laser Shock ◽  
Laser Shock Processing ◽  
Tc4 Titanium Alloy ◽  
Compressive Stresses ◽  
Maximum Value ◽  
Shock Processing

The aim of this article is to analyze the residual stresses field in a TC4 titanium alloy blade by laser shock processing (LSP).LSP is a new surface processing technology, it uses the laser shock wave to act on the surface of the target and form residual compressive stresses field. The ABAQUS software is applied to simulate the LSP of TC4 titanium alloy blade, and the distributions of the residual stresses field are analysed.After single LSP,the maximum value of residual stress on the surface is 309 MPa.The residual stresses on the surface increase first and then decrease.The residual stresses at the depth continue decreasing with the increase of the depth.After multiple LSP,the maximum value of residual stress on the surface is increased and plastically affected depth is increased.

Characterisation of WC-17Co and WC-9Ni HVOF Sprayed Cermet Coatings

2016 ◽  
Vol 840 ◽  
pp. 331-335
Author(s):  
Nur Amira Mohd Rabani ◽  
Zakiah Kamdi
Keyword(s):  
Steel Substrate ◽  
Optical Microscope ◽  
Binder Phase ◽  
High Porosity ◽  
Tungsten Carbides ◽  
Micro Hardness ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hardness Tester ◽  
Vickers Micro Hardness

Cemented tungsten carbides have been paid much attention due its better mechanical properties with excellent combination of hardness and toughness characteristics. The hard WC particles in the coating provide hardness and wear resistance, while the ductile binder such as Co and Ni contribute to toughness and strength. WC-17wt.% Co and WC-9wt.% Ni powders have been sprayed by the HVOF method to form coatings approximately 300μm and 150μm thick onto AISI 1018 steel substrate. Both coatings have been prepared and supplied by an external vendor. The coatings were examined using optical microscope (OM), scanning electron microscope (SEM), and X-Ray diffraction (XRD). The hardness of both coatings were also measured using Vickers micro-hardness tester. The microstructure of the coatings has been analyzed and found to consist of WC, brittle W2C phase, metallic W phase, and amorphous binder phase of Co and Ni. It is found that WC-Ni has a higher hardness value compared to WC-Co due to high porosity distribution.

Microstructure and Mechanical Properties of TC4 Titanium Alloy Subjected to High Static Magnetic Field

2017 ◽  
Vol 898 ◽  
pp. 345-354 ◽  
Author(s):  
Gui Rong Li ◽  
Fang Fang Wang ◽  
Hong Ming Wang ◽  
Jiang Feng Cheng
Keyword(s):  
Magnetic Field ◽  
Titanium Alloy ◽  
Dislocation Density ◽  
Static Magnetic Field ◽  
Micro Hardness ◽  
Tc4 Titanium Alloy ◽  
Tc4 Alloy ◽  
Deformation Ability ◽  
Magnetic Induction Intensity ◽  
The Magnetic Field

The TC4 titanium alloy was subjected to high static magnetic field (HSMF) treatment with different magnetic induced intensities (B=0、1T、2T、3T、4T、5T、6T and 7T). The effects of B on the texture, dislocation density, grain size, tensile properties and micro-hardness of TC4 titanium alloy were investigated, and the influence mechanism of magneto-plastic effect on the plastic deformation ability of titanium alloy was also been studied. The results showed that the dislocation density had been increased after the HSME treatment. It reached a maximum when B=2 T, which was enhanced by 1.6 times compared to that of the untreated samples. In the view of quantum scale,the magnetic field promoted the transition of radical pairs from singlet to triplet state, which caused the movement of dislocation, led to the dislocation depinning from the depinning center, and increased the flexibility of dislocation. Subsequently, the inevitability of optimized 2T parameter was further discussed in the dislocation pile-up. Furthermore, the magnetic field not only promoted the orientation preference of crystal plane along the slipping direction, but also had the effect on the grain refinement. Meanwhile the elongation had been increased due to HSMF treatment. The average elongation of TC4 alloy was 13.12% which was enhanced by 31.07% compared to that of the untreated sample which was 10.01%. And, the elongation increased with the increment of magnetic induction intensity B. The HSME treatment could also play a role in hardening alloys. When B=2 T the micro-hardness was 344.88 HV, which was increased by 8.09% compared to that without treatment. The micro-hardness was consistent with the change of the "point" of the dislocation density, which was characterized by dislocation strengthening.

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