Review: The effect of T4, T5, and T6 aluminium silicon magnesium copper (Al-Si-Mg-Cu) heat treatment on microstructure and mechanical properties for 4 stroke piston applications

Abstract

Al-Si-Mg-Cu alloy for four-stroke piston material replaces ferrous based material to obtain efficient engine work due to its lighter density. The aluminium alloy can be improved its mechanical properties by providing heat treatment instead of using the additional elements too much. The heat treatment is solution treatment - natural aging (T4), artificial aging (T5), and solution treatment - artificial aging (T6). The presence of heating makes precipitate regularity. The precipitates commonly occur in Al-Si-Mg-Cu alloys in heat treatment are θ-Al2Cu, β-Mg2Si, S-Al2CuMg, and Q- Al5Cu2Mg8Si6, or it is kind. α-Al acts as a matrix and is accompanied by the dispersion of Si particles. In the microhardness test, sequentially, the particles with the highest hardness are the Si, Q-Al5Cu2Mg8Si6, θ-Al2Cu, β-Mg2Si, and α-Al particles. Phase Q can withstand heat, and it is not easy to diffuse back to the matrix. The amount of phase Q depends on the addition of Cu and Mg. Heating that has optimal mechanical properties is T6 heating because the energy received for the formation of precipitates is more considerable than T4 and T5. When compared, the T6 quality index is higher.