强迫剪切条件下Ti-6Al-4V合金的绝热剪切失效

Adiabatic Shear Banding and Fracture in Ti-6Al-4V during Forced Shear Test

摘要: 采用分离式Hopkinson压杆(SHPB)加载装置,分别用200 mm和150 mm打击杆以28 m/s速度对Ti-6Al-4V合金帽形试样进行强迫剪切实验,利用OM、SEM、TEM等手段分析了强迫剪切条件下Ti-6Al-4V合金的绝热剪切带演化特征和高应变率剪切变形条件下的失效模式。结果表明,在本文所述实验条件下,Ti-6Al-4V合金的绝热剪切带(ASB)表现为“白亮带”;ASB的宽度随加载时间的延长而增加;ASB边缘的裂纹是由于ASB的变形与基体的不协调而产生的,ASB中心部位的裂纹是由于非晶形成而后破碎导致的。

Abstract: Mircrostrutural evolution of ASB and fracture mode during forced shear test in Ti-6Al-4V alloys has been investigated under OM、SEM、TEM.Tests were performed by using SHPB and hat sample, with strike bars 150 mm and 200 mm and the velocity of strike bar 28 m/s.The results showed that ASBs in Ti-6 Al-4 V alloys are “white bands”, the width of ASB is 9.2 μm under 150 mm strike bar, and 10.8 μm under 200 mm strike bar;the cracks in the center of ASB are caused by the breaking of amorphous, the cracks in the edge of ASB are caused by the imcompatible deformation between matrix and ASB.