基于残余应力和缺陷控制的非晶合金塑性提高及机理研究

项目名称： 基于残余应力和缺陷控制的非晶合金塑性提高及机理研究

项目编号： No.51471035

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 一般工业技术

项目作者： 薛云飞

作者单位： 北京理工大学

项目金额： 85万元

中文摘要： 非晶合金高度局域化的剪切断裂模式严重制约了该材料的工程应用。基于残余压应力能够有效稳定剪切带扩展过程和表面缺陷有利于诱发剪切带形核的认识，结合激光喷丸可以通过较小程度的冷作植入深度残余压应力的特点，本项目拟采用激光喷丸对非晶合金进行表面改性，通过引入深度残余压应力和较小尺度表面缺陷的方式提高非晶合金塑性。针对激光喷丸超高的脉冲压力可以诱发形成较厚非晶合金形变层的特点，开展冲击波加载下非晶合金的微结构演化和结构弛豫研究，揭示非晶合金基于键向有序和自由体积变化的微结构演化过程，阐明微结构改变对其热稳定性的影响，突破非晶合金残余应力分布的半定量描述。在此基础上，结合有限元模拟，研究残余应力和表面缺陷共同作用对非晶合金力学性能和损伤断裂模式的影响，揭示表面改性提高非晶合金塑性的机理。综合以上研究，采用全析因试验法，优化激光喷丸工艺参数，实现非晶合金塑性的极大提高，为非晶合金零部件的应用奠定基础。

中文关键词： 非晶合金；激光喷丸；残余应力；表面缺陷；力学行为

英文摘要： Bulk metallic glass (BMG) exhibits highly localized shear fracture mode, which restricts the engineering applications of BMG severely. Based on the understanding that residual compressive stress could stabilize the propagating process of shear band and surface defect could induce shear band nucleation effectively, combined that laser shock peening (LSP) could generate deep residual compressive stress with relatively low cold hardening, LSP is employed to introduce deep residual compressive stress and minor surface defect in BMG for improving the plasticity of BMG. Based on the fact that ultra-high pulse pressure of LSP could induce relatively thick deformed BMG layer, micro-structural evolution and relaxation of BMG under shock wave will be studied, revealing the change of body-orientational ordering and free volume, clarifying the effect of micro-structural changes on thermal stability of BMG, obtaining the semi-quantitative description of residual stress distribution in BMG. Based on the research referred above, combined finite element simulation, the effect of combined action of residual stress and surface defect on mechanical properties and fracture mode of BMG will be investigated in detail, revealing the mechanism of improved plasticity of BMG by surface modification, optimizing the process parameters of LSP by full factorial design, improving the plasticity of BMG greatly, and laying the foundation for the applications of BMG parts.

英文关键词： Metallic glass;Laser shock peening;Residual stress;Surface defect;Mechanical behavior