DH36钢中的动态应变时效特性

Dynamic strain aging characteristics in DH36 steel

利用准静态试验机和Hopkinson压杆装置对DH36钢在不同应变率和不同温度下的塑性流动应力进行试验研究。结果表明:预应变温度对DH36钢的力学性能有显著的影响;在动态应变时效温度区,出现时效强化所需时间较短;DH36钢塑性流动中出现的动态应变时效是由于温度和变形达到一定程度时,曾在林位错周围形成的溶质气团会沿着聚合的林位错通过管道扩散到运动位错处,并在位错附近形成溶质气团连续对位错形成拖曳,阻碍了位错运动,同时,在高温出现珠光体片间距减小,相界面增多,对位错运动的阻碍增大,因而也会导致塑性流动阻力提高。

To understand the dynamic strain aging phenomenon of DH36 high-strength vessel steel at different temperatures and different strain rates,and study its effects on mechanical properties,the flow stress of DH36 steel at different temperatures and different strain rates are experimentally studied by using universal material-testing machine and a split Hopkinson compression bar.The results obtained are as following： the pre-strain temperature has remarkably effects on mechanical properties of DH36 steel;In the temperature region of the dynamic strain aging,the time for aging strengthening is very short;The dynamic strain aging during the plastic flow of DH36 steel is due to following reasons,that is,when the temperature and strain rate reach a certain extent,the solute atmospheres ever around forest dislocations will diffuse to the mobile dislocations along collective forest dislocations by a pipe diffusion,then the formation of the solute atmospheres right round the mobile dislocation continuously drags and resists dislocation motion,meanwhile,the pearlite spacing reduction at the high temperatures and increases of the phase interfaces also lead to increasing resistance to dislocation,which further increases resistance to the plastic flow.