Tensile tests on laser additive manufactured of Nickel-based superalloy at seven temperatures are carried out.The failure mechanism and constitutive model of additive manufactured superalloy are studied through fracture analysis and data processing.The results show that the yield strength and tensile strength of Nickel-based superalloy decrease with the increase of temperature.When the temperature is higher than 673 K,the sawtooth flow phenomenon occurs in the plastic section,and the density of saw-tooth decreases with the increase of temperature.There are a lot of dimples and tearing edges on the frac-ture surface of the specimen,exhibiting significant ductile fracture characteristics.By considering the coupling effect of strain and temperature on the plastic behavior of the material,an improved constitutive model based on J-C and Z-A models is established to fit the flow stress of the alloy.The fitting values are in good agreement with the experimental values,and the absolute values of relative errors are all less than 4%.The finite element simulation results are compared with the load-displacement curves of the test,which further proves the accuracy of the constitutive model.
关键词
镍基高温合金/本构模型/流变行为/激光增材制造/有限元模拟
Key words
nickel-based superalloy/constitutive model/rheological behavior/laser additive manufacturing/finite element simulation
维普
万方数据