Effect of Heat Treatment on Microstructure and Mechanical Properties of Inconel 718 Alloy Fabricated by Selective Laser Melting [热处理对激光选区熔化成形Inconel 718合金显微组织结构和力学性能的影响]

作者：Zhang R.; Liu Z.; Huang J.; Zhu Q.; Xiao Z.^*

来源：Rare Metal Materials and Engineering, 2021, 50(1): 255-262.

• Heat treatment
• Inconel 718 alloy
• Mechanical properties
• Microstructure
• Selective laser melting

The effect of three different heat treatments, solution-aging (SA), homogenization+solution-aging (H+SA), and hot isostatic pressing+solution-aging (HIP + SA), on the microstructure and mechanical properties of selective laser melting (SLM) formed Inconel 718 alloy. The as-built Inconel 718 has a large number of dendritic structures, and there are many brittle laves phases precipitating among the interdendritic region. The δ phase is prone to precipitate when the alloy is treated by proper homogenization, but the material can not be strengthened without γ" and γ' phases. Hot isostatic pressing (1080℃, 148 MPa, 2 h) can considerably remove laves phases and micro pores of the as-fabricated samples, and combine with the solution aging treatment subsequently. It's conductive to refine the grain size of the as-built samples, flat the grain boundaries, and promote the precipitation of γ" and γ' phases, so HIP+SA treatment significantly increases the strength of Inconel 718 alloy. The mechanical properties of Inconel 718 alloy reach the optimum combination at UTS=1361 MPa, 0.2% YS=1191 MPa, and HV0.2=4900 MPa, and the elongation after breaking is 13.30%.

• 单位
  华南理工大学