加弧辉光离子渗NiCr与喷丸强化复合处理对钛合金微动疲劳性能的影响研究

研究了钛合金表面加弧辉光离子渗NiCr层的相组合和分布，对NiCr渗 层进行喷丸形变强化后处理，以协同提高钛合金耐微动疲劳性能。研究结果表明：利用加弧辉光离子渗技术可以获得由Ni3Ti金属间化合物等组成的渗镀复合层，从而提高钛合金的表面硬度和耐磨性能；NiCr渗层的耐磨性能与喷丸强化引入的表面残余压应力协同作用，使钛合金经加弧辉光离子渗NiCr和喷丸形变强化复合处理后的耐微动疲劳性能较单一喷丸强化处理更好。

The Effect ofGlow-discharge Ionized Nickel-chromizing with Arc Source and Shot Peening on the FrettingFatigue Resistance of Ti Alloy

Glow discharge ionized nickel chromizing with arc source was used to treat Ti5Al2.5Sn titanium alloy. The phases and constituent distribution in the treated surface were investigated by means of X ray diffraction and energy dispersive spectrometry. Shot peening was introduced to post treat the alloyed layer in order to synergically improve the fretting fatigue resistance of Ti alloy. The results show that a composite modified surface of NiCr coating over nickel chromium diffusion layer, which consists of N 3Ti and other phases, is formed on titanium alloy surface. Thus the hardness and wear resistance of titanium alloy are increased remarkably. As compared with the alloy subjected to shot peening alone, the titanium alloy after nickel chromizing and shot peening shows better fretting fatigue resistance. This is determined by the synergetic effect of the high wear resistance of the alloyed surface and the residual compressive stress induced by shot peening.