疏松含量对K465合金室温拉伸性能的影响

Effects of Shrinkage on the Tensile Properties of K465 Alloy at Room Temperature

K465是一种镍基铸造高温合金,具有良好的高温强度和优异的组织稳定性,应用于航空发动机的工作叶片和导向叶片上。采用相同铸造工艺制备了不同疏松含量的力学性能试样,并测试这些试样的室温拉伸性能。结果表明:当疏松含量从0.1%、1.23%到2.89%时,合金的抗拉强度从1069 MPa、1071 MPa到1091 MPa,延伸率从10%、9%到8%,对合金的拉伸性能没有造成较大的不利影响。室温拉伸断口上显示疏松不是主要裂纹源,与试样断裂没有明显的关联,当疏松含量为6.05%、7.94%和16.51%时,合金的抗拉强度从1012 MPa、990 MPa到780 MPa,延伸率从5%、3%到完全脆断,高含量疏松造成K465合金室温拉伸性能的明显下降,疏松成为主要裂纹源和裂纹的快速扩展通道。

Nickel-based cast superalloy K465 with the good properties at high temperature and the excellent stability of microstructure has been applied as a material of blade using in the high temperature field in the motor of plane.The specimens were the tested ones having finished the measurement of mechanical properties for master alloy using the same casting process.The tensile properties were tested at room temperature.When the shrinkage area was 0.1%,1.23%and 2.89%,the ultimate strength was from 1069 MPa,1071 MPa to 1091 MPa,and the elongation was from 10%,9%to 8%.The tensile properties were not degraded.Shrinkage was not principle crack initiation sites seen in the fracture surfaces.As a result,it was not related to the fracture of specimens and did not cause the change of tensile properties of specimens at room temperature obviously.When the shrinkage area was 6.05%,7.54%and 16.51%,the ultimate strength was from 1012 MPa,990 MPa to 780 MPa,and the elongation was from 5%,3%to 0.Hence,the tensile properties at room temperature were greatly decreased with the increase of shrinkage.Shrinkage was the principle crack initiation sites and rapid growth ways observed from fractured surfaces of tested specimens.