Effect of Heat Treatment on Microstructure and Mechanical Properties of Laser Deposited Haynes 282 Superalloy

摘要

The effect of heat treatment on the microstructural evolution and resulting mechanical properties of Haynes 282 alloy deposited with direct laser metal deposition have been investigated using SEM, EDS, and tensile test. A set of as-deposited specimens was solution heat-treated at 1120 °C for 2h followed by two-step aging (1010 °C/2h + 788 °C/2, 4, 6, 8, 16, 24h). The second and third sets of samples were only aged by two-step and one-step (788 °C), respectively. The microstructural investigation revealed an average gamma-prime precipitate size of 14.5 nm in the interdendritic region with 0.77% carbides in the as-deposited samples. Following aging, gammaprime particles were observed in both dendrite (14.5 nm) and interdendritic regions (22.5 nm) and carbides increased to 2.15%. One step aging at 788 °C/24h resulted in an excellent combination of room temperature yield strength of 950 MPa, UTS of 1240 MPa, and 18% elongation.