Study on microstructure and properties of Mg-Al-Si-Ca alloy by heat treatment

The effect of heat treatment on the microstructure and properties of Mg-4Al-0.25Si-0.3Ca alloy was sys-tematically studied. The results showed that after solution treatment at 420 degrees C for 10 h and 500 degrees C for 3 h, then aging at 220 degrees C for 7.5 h, the shape of Mg2Si and CaMgSi phases changed from continuous to dis-continuous, while the Mg17Al12 phased precipitated in the way of continuous precipitation in grains and discontinuous precipitation at grain boundaries during aging. The UTS of the alloy increased from 174.3 +/- 4.0 MPa to 194.0 +/- 5.0 MPa, and the corrosion current density decreased by 54%, The corrosion resistance was also improved, but the elongation decreased from 10.38 +/- 0.37% to 9.1 +/- 0.46%.(c) 2023 Elsevier B.V. All rights reserved.