Ti-6Al-4V钛合金固体渗硼法表面改性

对TC4钛合金(Ti-6Al-4V)进行表面渗硼使其表面硬度显著提高.渗硼温度为1000℃到1050℃,渗硼时间为5 h到20h.文内测量和比较了渗硼后钛合金表面的微结构、形貌、相组成等性质,研究了渗硼过程中Ti,Al,V,B等元素的扩散行为.在低温短时间渗硼时,渗硼层厚度仅0.8μm,而在高温长时间渗硼时,渗硼层厚度可达15 μm.实验证明,渗硼层由TiB和TiB2两相组成,并且它们的含量随渗硼温度提高而增加.渗硼层表面主要含TiB2,其显微硬度可达2200 HV0.01,渗硼层内表层主要含TiB,其显微硬度为1100 HV0.01.渗硼层的硬度远高于TC4钛合金的硬度.

Surface modification of Ti-6Al-4V alloy by pack boronizing

A pack boriding technique was employed to ohtain a hard coating on the surface of Ti-6Al-4V alloy in this paper.The diffusion process was carried out at various temperatures ranging from 1000 ℃ to 1100 ℃ for 5 to 20 hours.The microstructure,morphology and the phase composition of Ti-6Al-4V alloy after boriding were investigated.The diffusion behavior of Ti,Al,V,B elements in boronizing process was also discussed.The results showed that the thickness of diffusion layer ranged from 0.8 μm to 15 μm for different boriding parameters.The biphasic boron-titanium compounds TiB-TiB2 layer have formed on the surface of Ti-6Al-4V alloy.The XRD results of surface layer revealed that the amount of TiB and TiB2 increased with temperature rising.Furthermore,the surface B atoms reacted with Ti of Ti-6Al-4V matrix that led to the reduction of Ti in transition region.The microhardness value of TiB2 to TiB was gradient distribution ranged from 2200 HV0.01 to 1100 HV0.01.And the hardness value in the transition region was higher than the Ti-6Al-4V matrix.