激光冲击强化对TC17表面硬度的影响

TC17钛合金叶片耐磨性较差,在航空发动机恶劣的使用环境下受到冲刷磨损的作用易引发疲劳断裂。研究利用激光冲击强化技术对TC17钛合金进行表面强化,结果表明:激光冲击强化能够显著提高TC17材料硬度,提升材料抗冲刷磨损性能。从不同冲击参数强化后硬度测试结果得出,功率密度4GW/cm2、冲击三次为TC17钛合金最佳的激光冲击强化工艺参数,其硬度提高幅度达到10%以上,并且影响深度超过1mm。激光冲击强化过程中引入的表层晶粒纳米级细化及次表层高密度位错是材料硬度提高的主要原因。

Effect of laser shock peening on surface hardness of TC17 titanium alloy

Under severe environment,the vane of aeroengine,made of TC17 titanium alloy with poor wear resistance,is prone to result in a fatigue rupture caused by washing abrasion.By making use of the technology of Laser Shock Peening the surface of the material is strengthened,which results indicate that the technology can obviously improve the rigidity and boost up the wear resistance.It is known from hardness tests with different shock parameter that the power density 4GW/cm2 with three shocks is the best parameter for the hardness improving of TC17 titanium alloy.The hardness has been improved by 10% with an affected layer above 1mm thick.The nanocrystallization of the grain in the surface layer and the high-density dislocation in the hypo-surface layer are the dominating causation for hardness improvement.