Heat treatment and strengthening mechanisms of laser additive manufactured 6061 aluminum alloy

doi:10.13251/j.issn.0254-6051.2023.08.028

Abstract

Abstract: High strength 6061 aluminum alloy was printed by the laser powder bed fusion laser additive manufacturing technology. Firstly, the crack free 6061 aluminum alloy was obtained with the substrate preheating. And then, the printed alloys were heat treated, and the corresponding effect of heat treatments on the microstructure and mechanical properties was compared and analyzed. The results show that under the as printed (AP) condition, the alloy elements exist in the matrix in the form of supersaturated solution, and the tensile strength of the alloy is only 249 MPa. In the solution treatment (ST)+aging treatment (AT) and direct manual AT process, the mechanical properties of the aluminum alloy are significantly improved. After direct AT treatment, the alloy has high tensile strength and fraction elongation, 359 MPa and 12.5%, respectively. While after ST+AT, the alloy has a higher strength of 377 MPa and a lower elongation of 10.1%. The AT treatment is conducive to promoting the diffusion and precipitation of fine-needle Mg₂Si phase in the Al matrix, and the tensile strength of the alloy is significantly improved by the precipitate strengthening effect.

Key words: 6061 aluminum alloy, laser additive manufacturing, heat treatment process, microstructure and properties, strengthening mechanisms

CLC Number:

TG401

Chen Wentao, Yin Jing, Wang Chunyan, Hu Guiling. Heat treatment and strengthening mechanisms of laser additive manufactured 6061 aluminum alloy[J]. Heat Treatment of Metals, 2023, 48(8): 172-178.

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