【摘要】 对Fe-Ni-Nb-Ti-C合金在850℃变形后的等温弛豫过程中位错组态的演变以及应变诱导析出过程进行了TEM观察分析.样品的应力弛豫曲线可以明显地区分为三个阶段,分别对应应变诱导析出的孕育、形核长大和粗化过程.变形过程中产生的高密度、相互缠结的位错在等温弛豫过程中密度降低,并逐渐形成胞状结构.应变诱导析出在离散位错与胞界的位错网络上均能形核,但离散位错上颗粒析出密度更大.析出对位错产生的钉扎作用减缓了位错组态演变的进程.一旦析出颗粒发生粗化,则其钉扎作用减弱,而位错则以绕过机制摆脱析出颗粒的钉扎.更多还原

【Abstract】 Transmission electron microscopy (TEM) was used to investigate the evolution of dislocation configuration and the strain induced precipitation behavior during isothermal relaxation at 850 ℃ in a deformed Fe-Ni-Nb-Ti-C alloy. The stress relaxation curve can be divided into three stages, the incubation, nucleation and growth, and coarsening of strain-induced precipitates. The highly dense and twisted dislocations formed during the deformation develop into dislocation cells gradually and the density decreases with increasing relaxation time. The strain induced precipitates occur along the dispersed dislocations as well as the dislocation walls, while there are much more precipitates along the former. The dislocations were pinned by the precipitates which retard the evolution of the dislocation configuration. As the precipitates start to coarsen, the pinning effect becomes weak and finally the dislocations get rid of pinning through the bypassing mechanism.更多还原