【摘要】 利用分离式霍普金森压杆(SHPB)技术,对双态组织和片层组织Ti-6Al-4V合金帽形试样进行动态加载实验,通过控制加载时间(50,60和80μs)来研究绝热剪切带随时间的演化过程。微观分析结果表明:两种组织中绝热剪切带的宽度有一个发展过程,随着入射波加载时间的延长,绝热剪切带逐渐变宽;当加载时间为60μs时,两种组织钛合金中的绝热剪切带演化过程相同,均是在剪切应力下微观组织的拉长、细化和碎化;当加载时间为80μs时,双态组织中绝热剪切带的演化过程仍然是带内晶粒的进一步细化,而片层组织中的绝热剪切带中可能发生了动态再结晶。绝热剪切带演化过程的不同导致了绝热剪切带宽度的差异。更多还原

【Abstract】 In order to investigate evolution of adiabatic shear bands in typical microstructure (bimodal and lamellar microstructures) of Ti-6Al-4V alloy,the split Hopkinson press bar (SHPB) was used to impact hat-shaped specimens,and three impact bars of different length were used to control the loading time (50,60 and 80 μs). SEM and TEM were carried out to observe patterns of adiabatic shear bands (ASBs) in the specimens after impacting. The results showed that thickness of ASBs increased with the increase of loading time,and with the increase of loading time,evolution of ASBs in bimodal and lamellar microstructure was quite different. In lamellar microstructure,equiaxed structure was found in the specimen under the loading time of 80 μs,which might indicate that dynamic recrystallization happened. It led the thickness of ASB in lamellar microstructure thicker than that in bimodal microstructure.更多还原