Microstructure and mechanical properties analysis of CMT arc-additive manufactured 2319 aluminum alloy
The 2319-aluminum-alloy straight wall was fabricated with arc additive using CMT technology,and the microstructure and mechanical properties of 2319 aluminum alloy in deposited and heat-treated states were analyzed. For the as-deposited 2319 alloy,the intralayer zone is equiaxed crystal structure,and more porosity defects appear in the inter-layered zones. The grain distribution is a mixed one with coarse columnar and equiaxed crystals,with longitudinal tensile strength and transverse tensile strength of 251 MPa and 255 MPa respectively for the as-deposited 2319 aluminum alloy. The as-deposited 2319 aluminum alloy is strengthened by heat treatment,the solution and aging systems are optimized and the best heat-treatment system is determined based on hardness,i. e. solution at 535 ℃ for 1 h and aging at 175 ℃ for 12 h. After that,a high-density,fine and needle-like θ″Al2Cu phase can be introduced into 2319 aluminum alloy,resulting in precipitation strength-ening effect,which lifts tensile strength up to 449 MPa,76％higher than that without heat treatment.
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