摘要
利用超声表面纳米化技术(UNSM),采用两组静态载荷(15,30N)分别对A6061-T6铝合金表面进行处理获得强塑性变形层,利用光学显微镜、扫描电子显微镜和X射线衍射仪研究了由表面到基体的组织结构变化,并通过疲劳试验研究了合金的疲劳性能的变化。结果表明:载荷较大时,合金表面强塑性变形层深度和表面硬度均较大,表面残余压应力也大;超声表面纳米化处理后,试样表面粗糙度降低,合金表面获得等轴状且取向随机分布的纳米晶组织;处理后合金的疲劳破坏为剪切裂纹萌生机制,而处理前的为近表面微空洞或微缺陷处萌生机制。
A severe plastic deformation(SPD)layer on the surface of A6061-T6 aluminum alloy was obtained by ultrasonic nanocrystal surface modification(UNSM)technique at static loads of 15 N and 30 N.The microstructure from surface to matrix was examined using optical microscopy,scanning electron microscopy and Xray diffraction.Fatigue performance of the alloy was also studied by fatigue testing.The results show that the deep of SPD layer,surface hardness and surface residual compressive stress increased with the increase of static load.After being treated by UNSM technique,the surface roughness of samples declined,and the surface microstructure were isometric and random oriented nano-crystals.The fatigue fracture of A6061-T6 after UNSM showed the shearing crack initiation mechanism instead of typical subsurface facet or micro-void initiation mode before UNSM.
出处
《机械工程材料》
CSCD
北大核心
2014年第10期74-78,92,共6页
Materials For Mechanical Engineering
基金
国家自然科学青年基金资助项目(11202108)
教育部创新团队项目(IRT1027)
南通大学引进人才项目(03080453)
关键词
超声表面纳米化
铝合金
显微组织
ultrasonic nanocrystal surface modification
aluminum alloy
microstructure
