经不同温度下的拉伸试验,考察了几种热作工具钢的中温脆性。中温脆性随应变速度的下降和晶内强度的提高而趋于严重。本文分别考察了晶内位错运动速度和晶界滑移速度随变形温度的变化,进而证实中温脆性是在某一临界温度下,晶界滑移速度大于晶内位错运动速度,使变形高度集中于晶界而产生。 Tensile tests at different temperatures were conducted to investigate the medium temperature brittleness of several hot work tool steels. Medium temperature brittleness tends to be severe with decreasing strain rate and increasing intragranular strength. In this paper, the variation of intramolecular dislocation velocity and grain boundary slip velocity with deformation temperature were investigated respectively. Then it was confirmed that the medium temperature brittleness is that at a critical temperature, the grain boundary slip velocity is greater than the intragranular dislocation velocity and the deformation height Focus on the grain boundary and produce.