温度对X12CrMoWVNbN10-1-1钢组织及力学性能的影响

对X12Cr Mo WVNb N10-1-1耐热钢进行了300~600℃之间的高温力学试验,利用OM,SEM与TEM观察分析各温度下材料的微观组织及断口形貌,研究了温度对材料组织及高温力学性能的影响.结果表明:随温度升高,300~400℃,析出的脆性M3C相的数量和尺寸不断增加,且出现偏聚,析出强化和形变强化作用逐渐增强,塑性变形中,脆性相M3C处更容易出现应力集中,裂纹的产生、扩展更快,更易断裂,材料的塑性随之下降.400~600℃,碳化物发生转变,M3C相快速重熔分解,M7C3及M23C6开始析出,使得析出相的数量和尺寸下降,强化作用减弱;同时,动态回复作用越来越强,材料的强度快速下降,塑性快速上升.

Effect of Temperature on Microstructure and Mechanical Properties of X12CrMoWVNbN10-1-1 Steel

The high temperature mechanical tests of X12CrMoWVNbN10-1-1 heat-resistant steel were carried out with the different testing temperature in the range of 300~600℃. The microstructure and fracture morphology of the samples at different temperature tests were analyzed using OM， SEM and TEM. Effect of temperature on the microstructure and high temperature mechanical properties was studied. The results showed that when the testing temperature increased in the range of 300~400℃， the quantity and size of brittle M₃C carbides gradually increased and the segregation became more significant， resulting in an increase of precipitation strengthening and work hardening. For plastic deformation stage， the stress concentration and cracks were more prone to appear around M₃C carbides during deformation. The plasticity slowly decreased with temperature. When the temperature increased between 400℃ and 600℃， it was found that the carbides started to transform， M₃C carbides decomposed rapidly， M₇C₃ and M₂₃C₆ carbides gradually precipitated and the quantity of precipitations began to decrease， which resulted in a decrease of strengthening ability. Meanwhile，dynamic recovery became more significant and led to a dramatic decrease of strength and rapid increase of plasticity.