Performance Optimization and Mechanism of Arc Additive Manufactured Al-Zn-Mg-Cu Alloy Based on Heat Treatment

Abstract

Al-Zn-Mg-Cu high-strength alloys are widely used in aerospace structural materials because of their excellent properties. The microstructure of arc additive manufractured Al-Zn-Mg-Cu alloy deposition parts were analysed to optimize the performance via various heat treatment methods. The segregation of elements and solutes at grain boundaries and dendrite gaps were eliminated and the Zn and Mg atoms were fully dissolved into the Al matrix. The horizontal and vertical tensile strength increased from 243MPa to 513MPa and from 230MPa to 504MPa, relative to the normal deposited parts, respectively, and hardness distributed more uniformly in vertical direction increased from 119HV to 205HV. The performance enhancement was attributable to solid solution strengthening and precipitation strengthening.

Keywords: Al-Zn-Mg-Cu alloy, Arc additive manufacturing, Heat Treatment, Solid solution strengthening, Precipitation strengthening