【摘要】 研究了Zn-Al合金在较高加载速率条件下的绝热变形特性。通过ZA8,ZA27和ZA35合金在Hopkinson测试系统上的冲击压缩试验和冲击剪切试验,建立了材料的热粘塑性本构方程,分析了高应变率条件下的局部塑性失稳过程,得到了塑性失稳准则,揭示了局部塑性失稳的高应变率敏感性本质。研究指出,在由面心立方结构α相和密排六方结构η相组成的Zn-Al合金的塑性变形中,局部塑性失稳具有明显的应变率敏感性,组织中η相分数越多,塑性变形中产生的局部不协调效应越强烈,局部失稳的应变率敏感性越高。更多还原

【Abstract】 Adiabatic deformation character of the Zn-Al alloys at higher loading rate was investigated.The thermal viscoplastic constitutive equation was established by the impact compression and the impact shearing tests by the split Hopkinson pressure bar(SHPB),the process of local plastic instability at higher strain rates was analyzed,the criterion of plastic instability was obtained,and the nature of the high strain rate sensitivity for local plastic instability was revealed.It is suggested that the local plastic instability of Zn-Al alloys composed of face-centered cubic(FCC) phase α and hexagonal close-packed(HCP) phase η is sensitive to strain rate in plastic deformation;the more the η-phase fraction in microstructures exists,the more intensively the effect of the incoordination in plastic deformation shows and the higher the strain rate sensitivity of local instability is.更多还原