涂层对钛合金激光冲击效果的影响

Effect of coating on titanium alloy during laser shock processing

激光冲击波可以用来对比较难成形的材料进行精密成形,而材料表面的涂层在激光冲击过程中起到重要的作用,因而研究了涂层对零件冲击效果的影响.试验中,当激光功率密度达到109W/cm2以上,脉宽为22.1 ns,波长为1.06μm时,分别对黑漆涂层以及不加涂层的钛合金TA2进行激光冲击,发现涂层不仅能提高激光能量的吸收,而且能显著地提高冲击压力.通过激光冲击后的形变测量,发现使用黑漆涂层,相对于不加涂层,其变形量提高了471%,表面残余压应力达到-212.2MPa,有效改善了钛合金的疲劳寿命.采用涂层可以延长航空工业上许多关键零部件的服役寿命.

Laser shock peening can be used to form metals or alloys into precise shapes without their yielding. The effects of coating during laser shock processing are introduced. The targets are irradiated by laser pulses of 22. 1 ns duration at laser power density around 10^9 W/cm^2 and wavelength 1.06μm. The laser shock process with titanium paint and unpaint are used respectively. It shows that the coating can increase the shock pressure amplitude and the laser density absorption; the compressive residual stresses at the surface of the workpiece is about 212.2 MPa, and the deformation is increased by at least 471%, which results in significantly improved fatigue properties and stress corrosion cracking in titanium components. The method has a potential as a means of components coating in aerospace and defense applications.