喷丸处理对6151-T6铝合金旋转弯曲疲劳性能的影响  

Effect of Shot-peening on Fatigue Behavior of 6151-T6 Aluminum Alloy Under Rotating Bending

作　　者：张艳斌[1] 鲁连涛[1] 薛弼一[1] 

机构地区：[1]西南交通大学牵引动力国家重点实验室,成都610031

出　　处：《材料工程》2014年第4期73-78,共6页Journal of Materials Engineering

基　　金：国家科技支撑计划资助项目(2009BAG12A01-K02,2009BAG12A04-D02);西南交通大学牵引动力国家重点实验室开放课题资助项目(TPL1205)

摘　　要：对经过电解抛光、喷丸处理和喷丸处理再抛光的三种6151-T6铝合金试样的表面粗糙度及喷丸处理后试样表面硬化层的硬度进行测试。对三种表面状态不同的铝合金材料进行旋转弯曲疲劳实验。研究喷丸处理试样表面残余应力随疲劳实验的变化情况,以及喷丸处理对该铝合金疲劳性能的影响。结果表明:喷丸处理对材料疲劳性能的影响与加载的压应力水平有关。当加载的压应力与表面残余压应力之和不超过材料表面硬化层的循环屈服强度时,硬化层中的残余压应力在疲劳过程中不发生应力松弛,疲劳寿命得到大幅度提高;反之,将发生应力松弛现象,疲劳寿命的提高程度受残余压应力松弛程度的影响。此外,喷丸处理造成的材料表面粗糙度的增加,在全应力幅范围,使材料的疲劳寿命略有降低。The surface roughness of electro-polishing,shot-peening and polishing after shot-peening 6151-T6 aluminum alloy samples were measured together with Vickers hardness on the surface hardness layer of the shot-peening samples.Fatigue tests of the aluminum alloy with different surface conditions were performed under rotary bending loading.The residual stress on the surface for the shotpeening specimen was measured during the fatigue test,and the effect of shot-peening on fatigue behavior of the aluminum alloy was investigated.The results show that the effect of shot-peening on fatigue behavior of the material depends on the applied cyclic compressive stress level.Shot-peening improves fatigue life of the material when the compressive stress （sum of applied compressive stress and residual compressive stress） on the surface layer is below the cyclic yield strength of the layer.The great improvement of fatigue life is due to the fact that residual compressive stress induced by shotpeening cannot be released during fatigue tests.On the contrary,the residual compressive stress can be released when the compressive stress on the surface layer exceeds the cyclic yield strength of the layer.The improvement degree of fatigue life is affected by the extent of residual stress relaxation on the surface.Besides,the surface roughness induced by shot-peening slightly decreases the fatigue life of the material in the full stress amplitude range.

关 键 词：铝合金 疲劳 喷丸 应力松弛 

分 类 号：O346.2[理学—固体力学]