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研究双辊铸轧和热轧处理AZ31B镁合金板材在室温和应变速率从0.001 s~(-1)到375 s~(-1)条件下的动态拉伸力学行为,以及力学性能与显微结构之间的关系。实验发现,该镁合金板材具有很强的初始基面纤维织构,并且在高应变速率条件下机械孪生成为主要的变形机理。材料的屈服强度和拉伸极限强度随应变速率的提高而提高;然而,孪生诱导的软化效应导致应变强化指数随应变速率的提高而成比例地降低。在准静态拉伸条件下,断裂伸长率随应变速率的提高而明显地降低;而在动态拉伸条件下应变速率对断裂伸长率的影响却不明显。最后,应用扫描电镜对拉伸试样进行了断口形貌分析。分析结果表明,该加工状态下的AZ31B镁合金板材的拉伸断裂是一种韧性与脆性混合断裂模式。
The dynamic tensile behavior of AZ31B magnesium alloy sheet treated by twin-roll casting and hot rolling at 0.001 s -1 and 375 s -1 at room temperature and strain rate was studied. And the mechanical properties and microstructure The relationship between. The experimental results show that the magnesium alloy sheet has a strong initial basal fiber texture, and mechanical twins become the main deformation mechanism under high strain rate conditions. The yield strength and ultimate tensile strength of the material increase with increasing strain rate; however, twin induced softening effects cause the strain hardening exponent to decrease proportionally with increasing strain rate. Under quasi-static tensile conditions, the elongation at break decreases obviously with the increase of strain rate. However, the effect of strain rate on the elongation at break is not obvious under the dynamic tensile conditions. Finally, the tensile fracture morphology of the tensile specimens was analyzed by scanning electron microscopy. The results show that the tensile fracture of AZ31B magnesium alloy sheet is a ductile and brittle mixed fracture mode.