Optimisasi Sifat Mekanik Paduan Mg AZ91: Pengaruh Proses Thixoforming dan Homogenisasi terhadap Kekerasan, Kekuatan Tarik, dan Mikrostruktur
DOI:
https://doi.org/10.55893/jt.vol24no1.680Keywords:
homogenizing, Mg AZ91 alloy, thixoformingAbstract
The Mg AZ91 alloy is commonly utilized in the automotive and aerospace sectors due to its excellent strength-to-weight ratio. However, to expand its usability, enhancements in its mechanical properties through specific treatments are required. This study investigates the impact of thixoforming and homogenization on the hardness, tensile strength, and microstructure of the Mg AZ91 alloy. Testing was carried out under four conditions: as-cast, as-cast with homogenization, thixoforming, and thixoforming combined with homogenization. Results revealed that the highest hardness value (108.8 HB) was achieved in the thixoformed and homogenized sample, compared to 65.1 HB in the as-cast condition. The tensile strength also increased significantly from 148.3 MPa to 299.4 MPa, with yield strength rising from 82.6 MPa to 277.2 MPa. Elongation improved slightly from 12.1% to 14.475%. Microstructural analysis showed a transition from coarse dendritic formations in the as-cast condition to a refined, equiaxed structure with uniform alpha and beta phase distribution following thixoforming and homogenization. Although porosity and impurities were present in all samples, they were more effectively managed after homogenization. These findings indicate that combining thixoforming with homogenization effectively enhances the mechanical properties and microstructure of Mg AZ91 alloy, increasing its suitability for high-performance engineering applications.
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