选区激光熔化成形Inconel 625合金的显微组织及力学性能

摘要

The Inconel 625 alloy powder was prepared by the powder atomization method,and then the metallographic,tensile and impact specimens were directly formed with the alloy powder by the selective laser melting technology.The surface residual stresses,microstructures and mechanical properties of the specimens before and after annealing were studied.The results show that a small amount of micro cracks were observed at the surface of the specimen and few oxycarbide inclusion particles existed inside the specimen.The microstructure was uniformity and dense and consisted of the single austenite phase.The surface residual stress of the specimen before annealing was 398 MPa,which was higher than 242 MPa of the specimen after annealing at 1 140 ℃ for 2 h.The average yield strength,tensile strength,impact energy,percentage elongation and reduction of area were 743 MPa, 1 043 MPa,139 J,31.4% and 49.6% respectively.After annealing,the yield strength and tensile strength of the specimen decreased while the impact energy,percentage elongation and reduction of area improved.The tensile and impact fracture of the specimen before annealing showed a ductile fracture characteristic.%采用雾化方法制备了Inconel 625合金粉,利用选区激光熔化成形技术将该合金粉直接成形制备了金相、拉伸和冲击试样,研究了其表面残余应力、显微组织及退火前后的力学性能.结果表明：试样表面有少量微裂纹,内部存在少量碳氧夹杂物颗粒,显微组织均匀致密,由单一奥氏体相组成；退火前试样的表面残余拉应力为398 MPa,高于经1140℃×2 h退火处理后试样的(242 MPa),其平均屈服强度、抗拉强度、冲击功、断后伸长率和断面收缩率分别为743 MPa,1043 MPa,139 J,31．4％和49．6％,而退火处理后试样的屈服强度、抗拉强度降低,冲击功、伸长率和断面收缩率有所增加；退火前试样的拉伸和冲击断口均呈韧性断裂特征.