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利用脉冲式Nd:YAG激光在Ti6Al4V合金表面进行激光渗氮处理,借助纳米压痕和划痕试验表征渗氮层的弹塑性力学性能。结果表明,在钛合金表面成功制备了高硬度、高强度、枝晶状分布的渗氮层。同时,渗氮层内硬度、模量、强度以及应力-应变关系、摩擦系数等力学性能呈现出类似于激光渗氮层内氮元素扩散曲线的非均匀性空间分布规律。硬度和弹性模量之比以及纳米划痕试验结果表明,激光渗氮层的抗磨损性能随深度的增加逐渐降低,摩擦系数随着划入深度的增加,从0.2增加到0.4。
The laser nitriding treatment was performed on the surface of Ti6Al4V alloy by pulsed Nd: YAG laser. The elasto-plastic mechanical properties of the nitrided layer were characterized by means of nanoindentation and scratch test. The results show that nitrided layer with high hardness, high strength and dendrite distribution has been successfully prepared on the surface of titanium alloy. At the same time, the mechanical properties such as hardness, modulus, strength, stress-strain relationship and coefficient of friction in the nitrided layer show a non-uniform spatial distribution similar to that of the nitrogen diffusion in the laser nitrided layer. The ratio of hardness and elastic modulus and the results of nano-scratch test show that the wear resistance of laser nitrided layer decreases with the increase of depth, and the friction coefficient increases from 0.2 to 0.4 with the increasing depth.