Indentation-Derived Creep Response of Age-Hardened AlSi10Mg Fabricated Through Powder Bed Fusion Process

This work mainly focuses on investigating the microstructural and indentation creep behaviour of heat-treated AlSi10Mg alloy processed via the laser-assisted powder bed fusion (PBF) route. The as-built AlSi10Mg samples were initially solutionized at 520 °C for 2 h. Then, the solutionized samples were aged at 180 °C for 2 h. Indentation creep tests were conducted on the aged sample at three different loads 55, 92 and 129 MPa at 100 °C for 2 h. The steady-state creep rate was calculated from the slope of time vs indentation depth graph. In order to supplement the indentation creep results, detailed microstructural analysis has been carried out through optical and scanning electron microscopy. XRD study was carried out for phase analysis. AlSi10Mg in the as-built condition revealed the eutectic mixture at the melt pool boundaries and ultrafine Al cells in the interior. XRD pattern confirmed the presence of Mg 2 Si in the age-hardened condition. Several defects were seen in the age-hardened condition. As-built alloy showed the highest hardness, whereas age hardening reduced the hardness due to the spheroidization of Si particles. The primary creep region showed an increase in indentation depth increased with respect to time. The depth of indentation remained constant in the secondary creep region. Age-hardened samples subjected to 92 MPa stress showed better creep resistance compared to 55 and 129 MPa. As-built condition showed the highest hardness due to the extremely fine microstructure.