Heat treatment to eliminate anisotropy of microstructure and high-temperature tensile properties of GH4169 superalloy by selective laser melting

The selective laser melted （SLM） GH4169 superalloy has a significant directional columnar dendritic solidification microstructure， which can cause severe mechanical property anisotropy and increase service risk. The GH4169 superalloy prepared by laser selective melting （SLM） technology is taken as the research object， and two different heat treatment processes are designed： hot isostatic pressing+standard solid solution+double aging and hot isostatic pressing+homogenization heat treatment+standard solid solution+double aging for post-heat treatment of the prepared alloy. The effect of two heat treatment processes on the anisotropy of microstructure and high-temperature tensile properties of GH4169 superalloy prepared by laser selective melting is investigated. The results show that the homogenization heat treatment eliminates the Laves phase， and the columnar crystal structure of the as-built GH4169 alloy transforms into an equiaxed crystal structure. The high-temperature tensile results show that the high-temperature tensile strength ratio and plasticity ratio of GH4169 alloy in the transverse and longitudinal directions without homogenization treatment are 1.10（1145/1040） and 0.83（10.2/12.2）， respectively. The high-temperature tensile strength ratio and plasticity ratio of GH4169 alloy in the transverse and longitudinal directions after homogenization heat treatment are 1.00（1041/1038） and 1.00（8.6/8.6）， respectively. The anisotropy of microstructure and mechanical properties of GH4169 alloy prepared by laser selective melting is eliminated.