Effect of heat treatment time on the microstructure and mechanical deformation behavior of additive-manufactured AlSi10Mg components

The AlSi10Mg alloy was developed using a selective laser melting (SLM) process, followed by stress relieving at 300∘C\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$300^\circ \hbox {C}$$\end{document} for 2 and 4 h respectively. The effect of the heat treatment time on the microstructural and mechanical properties was determined. AlSi10Mg powder with an average particle size of 47μm\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$47\,\upmu \hbox {m}$$\end{document} was successfully melted with laser energy density of 53.7J/mm3\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$53.7\,\hbox {J/mm}^{3}$$\end{document}. The samples were examined using both a scanning electron microscope and an optical microscope, to determine their microstructural properties. The samples were subjected to a tensile test and nano-indentation in order to determine the effect of heat treatment time on the microstructures and mechanical properties. The 2-h stress relieved alloy revealed fine silicon precipitates within the semi-elliptical track. The 4-h stress relieved alloy formed coarser silicon precipitates without semi-elliptical tracks. The results showed: improvement in deformation behaviour, with an increase in stress-relieving time; while the strength was compromised. The 2-h stress relieved sample showed higher strength, due to the fine silicon precipitates, when compared to the 4-h stress relieved sample, which showed excellent ductility. The lower strength was attributed to coarser silicon particles within the microstructure.