晶界M_(23)C_6碳化物对IN 617合金力学性能的影响

Effect of Grain-Boundary M_(23)C_6 Carbides on Mechanical Properties of Inconel Alloy 617

研究了IN 617合金在760℃时效过程中组织结构与室温冲击和拉伸性能的关系,并借助扫描电镜和透射电镜对合金时效过程中的微观结构、室温冲击及拉伸断口进行了观察与分析.结果表明:在IN 617合金时效后,主要析出相为M23C6碳化物;晶界M23C6碳化物对强度和塑性、冲击吸收能量的作用是:一方面,它阻碍晶界滑移,起到强化作用,从而提高了合金强度;另一方面,它导致界面结合强度降低,晶界成为断裂的发源地,从而引起冲击吸收能量和塑性降低;合金时效后,断裂模式由塑性断裂转变为脆性断裂.

The relationship between microstructure and impact/tensile properties of alloy IN617 was investigated after aging at 760（°C）.The microstructure of the alloy during aging process,and the fracture surface after impact and tensile tests at room temperature were analyzed by means of scanning electron and transmission electron microscopy.Results show that M_（23）C_6 carbide exists within the matrix as major precipitates after aging,and the effect of M_（23）C_6 at grain boundary on properties of the alloy is contradictory.On the one hand,the strength of the alloy is intensified by the carbides due to its obstruction effect on boundary migration.On the other hand,the bonding strength at interfaces is weakened by initiation of cracks at that area,leading to a continuous decrease of the impact absorbed energy and ductile properties.The fracture mode of the alloy changes from the ductile to brittle pattern after aging.