Philippine Journal of Science
154 No. (1): 37-45, February 2025
ISSN 0031 – 7683
Date Received: 25 April 2024

Ayrah Andrea M. Marterior, Carla Joyce C. Nocheseda,
and Mary Donnabelle L. Balela

Aluminum (Al) alloys A356 and AlSi10Mg of the Al-Si-Mg system, considered counterparts, possess high industrial value due to their high strength-to-weight ratio and excellent mechanical properties. A356 is manufactured by conventional processes like casting, whereas AlSi10Mg is used to additively manufacture A356 by direct metal laser sintering. T5 and T6 heat treatment are widely employed on cast and wrought Al alloys to increase their strength, hardness, and other mechanical properties. Since AlSi10Mg is a relatively novel material and 3D printing is a new manufacturing technique, the standard T5 and T6 heat treatment conditions cannot be directly used. As such, this work studied the effects of T6-like (solutionizing, quenching, aging) and T5-like (direct aging) heat treatment on the cast and 3D-printed Al-Si-Mg alloys. The hardness of cast A356 increased from 58.6 to 85.6 HV while retaining its dendritic microstructure under
T6. Then again, the hardness decreased after T5-like heat treatment at 100–400 °C. 3D-printed AlSi10Mg under T6 showed visible microstructure coarsening with decreasing hardness from 115 to 96 HV (along the z-direction). Under T5, the hardness significantly reduced at 300–400 °C. Results show that even slight temperature or time changes during heat treatment produce varying results. Ultimately, this work contributes to developing more accurate heat treatment procedures for 3D-printed Al-Si-Mg systems.