20Zr-70Ti-6Al-4V合金静动态力学性能研究

The static and dynamic mechanical properties of 20Zr-70Ti-6Al-4V alloy

摘要:

本文以20Zr-70Ti-6Al-4V合金为研究对象，采用XRD、DSC、OM和SEM等测试分析技术，研究了合金在退火处理和固溶时效处理过程中的相变及组织演化规律，并通过万能试验机和分离式霍普金森压杆，进一步研究了组织与应变速率对合金静动态力学性能的影响。结果表明：20Zr-70Ti-6Al-4V合金经退火和固溶时效后均由α相和β相组成，呈现为网篮组织，在静态加载条件下，抗拉强度最高可达1301MPa，塑性应变最高可达14.9%，抗压强度最高可达1386MPa，断裂方式为韧性断裂；在动态加载条件下，应变速率处于1000s-1到3000s-1这一高应变率范围时，20Zr合金的动态抗压强度有明显提高，表现为应变率强化效应，在同一应变速率下，20Zr合金固溶时效态的抗压强度和失效应变均高于退火态；动态压缩试样表面观测到与压缩轴呈45°角的宏观裂纹，动态破坏模式为绝热剪切失稳破坏。

Abstract:

This study aims to evaluate the static and dynamic mechanical properties of 20Zr-70Ti-6Al-4V alloy. The XRD, DSC, OM and SEM were used to test and analyze the phase transition and microstructural evolution of the 20Zr alloys subjected to different heat treatments. Dynamic compression tests were conducted by the SHPB(split Hopkinson pressure bar) to study the dynamic mechanical properties. The results showed that all 20Zr alloys were comprised of α and β phase and presented typical basketweave microstructures. At static conditions, the tensile strength was up to 1301 MPa., the plastic strain up to 14.9%, while the compressive strength was up to 1386 MPa. Under dynamic compression experiments, the dynamic compressive strength increased as the strain rate increased from 1000s-1 to 3000s-1, which reflected the strain hardening effect. In addition, the dynamic compressive strength and the plastic strain of 20Zr alloys undergoing the solid solution and aging treatment exceeded the anneal treated alloys. Besides, the failure of alloys resulted from the adiabatic shear bands.