摘要
为了提高Al-12Si合金在高温工况下的服役寿命,文中基于喷丸强化技术,探究了表层组织细化和压应力对材料疲劳性能的影响。采用微观表征手段对组织结构进行表征,通过X射线残余应力分析仪、显维维氏硬度仪以及常温旋弯疲劳试验机对喷丸强化后材料的表面残余应力、硬度及疲劳性能进行评价。研究结果表明:喷丸强化有效改善了初生硅的大小和圆整度,硅相平均尺寸由40μm降至30μm,圆整度由基体的1.69提高至2.09,且其对Al7Cu4Ni尺寸影响较大,由基体的47μm2降至10.87μm2,另其可在Al-12Si合金表面引入170 MPa残余压应力。喷丸强化引入的应变强化可使Al-12Si合金的硬度由117 HV提高至200 HV以上。常温旋弯疲劳实验表明,喷丸强化促使Al-12Si合金的疲劳强度提高了13%以上。
The study is intended to improve the service life of Al-12Si alloy at high temperature.Based on the shot peening technology,the effect of surface microstructure refinement and compressive stress on the fatigue properties of the material was investigated.The microstructure was characterized by means of micro characterization.The surface residual stress,hardness and fatigue properties of the material strengthened by shot peening were evaluated by an X-ray residual stress analyzer,an apparent dimensional Vickers hardness tester and a normal temperature rotary bending fatigue tester.The results show that shot peening can effectively improve the size and roundness of the primary silicon.The average size of silicon phase decreases from 40μm to 30μm and its roundness increases from 1.69 to 2.09.And shot peening has a great influence on the size of Al7Cu4Ni,decreasing from 47μm2 of the matrix to 10.87μm2.It can introduce 170 MPa residual compressive stress on the surface of Al-12Si alloy.The hardness of Al-12Si alloy can be increased from 117 HV to 200 HV by strain hardening.The results show that shot peening improves the fatigue strength of Al-12Si alloy by more than 13%.
作者
姚敏
王萍
YAO Min;WANG Ping(School of Materials and Chemical Engineering,Xi’an Technological University,Xi’an 710021,China)
出处
《西安工业大学学报》
CAS
2020年第4期420-427,共8页
Journal of Xi’an Technological University
基金
陕西省重点研发计划项目(2018GY-111)
陕西省教育厅产业化培育项目(17JF009)
榆林科技计划项目(2018-2-30)。
