Microstructure and properties of novel AlSi11CuMn alloy manufactured by selective laser melting

[Display omitted] •The coefficient of thermal expansion of the AlSi11CuMn alloy manufactured by SLM is 19.1·10−6 °C−1.•The hardness of the as processed AlSi11CuMn alloy is 144HV.•The ultimate tensile strength of 354 MPa and elongation of 5.4% were obtained after heat treatment. The microstructure and mechanical properties of the novel AlSi11CuMn alloy manufactured by selective laser melting were investigated in the as processed state and after heat treatment. A fine eutectic structure formed in the as processed alloy. A duplex size structure formed after solution treatment. The thermal expansion coefficient was 19.1·10−6 °C−1 in the 20–100 °C range which is typical for cast Al-Si alloys. Increasing annealing temperature from 190 to 275 °C leads to a sharp decrease in the alloy hardness from 136HV to 119HV after 2.5 h. The hardness was significantly reduced from 136HV to 79–82HV after solution treatment at 515 °C. The yield stress, ultimate tensile strength and elongation were 288 MPa, 354 MPa and 5.4%, respectively after solution treatment at 515 °C and aging at 180 °C for 8 h.