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Influence of multiple laser peening on vibration fatigue properties of TC6 titanium alloy
摘要： In this study, typical TC6 titanium alloy was taken to investigate the effects of multiple laser peening (LP) on the vibration fatigue properties and microstructural evolution. The vibration fatigue experiments were conducted, while the vibration fatigue life of the specimens before and after LP was compared and the fracture morphologies were observed by scanning electron microscopy (SEM). In addition, the measurements of residual stress and microhardness were carried out. The microstructures produced by different treatments were also characterized by transmission electron microscopy (TEM) and electron backscattered diffraction (EBSD). The experimental results indicated that multiple LP could indeed enhance the vibration fatigue properties of TC6 titanium alloy. Comparing with the investigated specimen without LP, the vibration fatigue life of the specimen subjected to 5 times LP increased by 105.2%. Meanwhile, after 5 times LP, the surface residual stress transformed from tensile stress (+26 MPa) to compressive stress (?485 MPa), and the surface microhardness was 428 HV, which increased by 32.9% compared with the untreated sample. Additionally, high-density of dislocation and deformation twin were also generated after multiple LP. The improvement of vibration fatigue properties was attributed to the rewarding compressive residual stress and the beneficial microstructural evolution induced by multiple LP.
关键词： TC6 titanium alloy,Laser peening,Vibration fatigue properties,Microstructure evolution,Residual stress
更新于2025-11-14 17:04:02
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A comparative study of laser metal deposited and forged Ti-6Al-4V alloy: Uniaxial mechanical response and vibration fatigue properties
摘要： This paper conducts a comparative study on mechanical properties of LMD and forged Ti-6Al-4V, focusing on uniaxial compression, tension and shear response with different strain rates, and vibration fatigue behaviors with 45–50 Hz in frequency. The micro-observation on initial microstructures and fractures explains the mechanism of lower uniaxial strength, shorter fatigue life, and larger dispersion in fatigue life and fracture position of LMD sample compared with the forged counterpart. Initial void defects within LMD sample tend to be stress-concentration zone, further initiating fatigue cracks. The columnar β grains leads to anisotropy of fatigue life and crack propagation for LMD sample.
关键词： Fracture analysis,Laser metal deposition,Vibration fatigue,Initial defect,Ti-6Al-4V
更新于2025-09-23 15:21:01
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Gradient microstructure and vibration fatigue properties of 2024-T351 aluminium alloy treated by laser shock peening
摘要： To investigate the improvement in vibration fatigue and the strengthening mechanism of laser shock peening, a nanosecond laser was used to strengthen the 2024-T351 aluminium alloy. Accordingly, the microstructure, residual stress, nanohardness and surface roughness of the treated alloy were measured. Subsequently, the vibration fatigue damage and fatigue life were evaluated, and the vibration fracture morphology was observed. The results showed that the grains in the peened surface were re?ned. A residual stress of ?141 MPa and a nanohardness of 3.1 GPa were obtained by laser shock peening. Based on the relationship between the peened microstructure and fracture morphology, it was deduced that an increase in the grain boundaries led to a lower crack initiation rate and a higher crack initiation life. The compressive residual stress decreased the crack growth rate and increased the crack growth life. Therefore, laser shock peening increases the total vibration fatigue life by about 63.5%.
关键词： Laser shock peening,Vibration fatigue,2024-T351 aluminium,Compressive residual stress,Microstructure
更新于2025-09-23 15:21:01