碳离子注入对Ti—6Al—4V合金疲劳寿命的改善

3×10~(17)Cion/cm~2在80keV的能量下注入到Ti-6Al-4V合金中。在应力控制的拉-零试验条件下,发现C~+注入试样的疲劳极限提高了28%。利用扫描电镜、透射电镜和二次离子质谱等研究了试样在注入前后和疲劳前后的表面层微观组织与结构以及注入元素沿表面层深的浓度分布。结果表明,注入层的微观组织中含有大量的辐照损伤并有许多细小的TiC相颗粒;注入与未注入试样的裂纹源在低应力疲劳中出现在亚表面区;注入元素在循环载荷作用下向基体中扩散。

IMPROVEMENT ON FATIGUE LIFE OF Ti-6Al-4V ALLOY BY CARBON ION IMPLANTATION

The fatigue limit of Ti-6Al-4V alloy could be improved over 28% byimplantation of a dose of 3×10~(17) ion/cm~2 of C at 80 keV under stress-controlledtension-zero condition. The microstructure of surface layer, whether implanted ornot, and before or after fatiguing, as well as the concentration distribution of imp-lanted ion along the depth of surface layer were examined by SEM, TEM andSIMS. A great deal of radiation damages and a good many fine TiC particles arefound in the implanted layer. The fatigue cracking origins, implanted or not, occurin subsrface under lower stress and longer fatigue life. And the implanting speciesdiffuse into substrate under cyclic loading.