Research on Microstructure and Mechanical Properties of Wire Arc Additive Manufactured Aluminum-Lithium Alloy
Lithium aluminum(Al-Li)alloy is a new-generation lightweight alloy material used in aerospace applications.In this study,arc additive manufacturing was used to fabricate aluminum-lithium-silicon alloy.A comparison was made between the microstructure and mechanical properties of the alloy in the as-deposited sample and the T6 heat-treated sample.The experimental results show that the average size of the α-Al phase in the single-pass thin-walled deposited aluminum-lithium-silicon alloy was approximately 21.2 μm.SEM and XRD results revealed the presence of a large amount of micrometer-scale eutectic Si phase and eutectic phases containing Cu and Li in the microstructure.After T6 heat treatment,the coarse Al2Cu phase and some eutectic silicon structures gradually dissolved into the matrix.The hardness of the additive sample increased from 96HV to 138HV,representing a relative increase of 43.8%.The tensile strength in the 0°,45°,and 90° directions was 402 MPa,350 MPa,and 330 MPa,respectively.The as-deposited samples exhibited tensile strengths of 160 MPa,134 MPa,and 142 MPa in three directions,whereas the T6 heat-treated samples showed significantly improved mechanical properties.
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