Pengaruh Jenis Cetakan terhadap Sifat Mekanik dan Mikrostruktur pada Al-Cu yang Digunakan Sebagai Material Alternatif pada Rumah Roller Sepeda Motor Matic

Abstract

This research aims to analyze the effect of mold type on the mechanical properties and microstructure of Aluminum-Copper (Al-Cu) alloy used as an alternative material for the roller housing in automatic motorcycles. The study employs an experimental approach utilizing two casting methods: sand casting and permanent mold casting. The alloy consists of 96% aluminum and 4% copper. Mechanical testing includes Brinell hardness, Charpy impact, wear resistance, and metallographic analysis.The results demonstrate that the casting method significantly influences the material’s quality. The permanent mold casting produced a finer, denser, and more homogeneous microstructure with uniformly distributed copper and minimal porosity. This led to improved impact strength (0.0759 J/mm²) and better wear resistance (1.019 × 10⁻⁸ mm³/Nmm), although the hardness value (62.154 BHN) was slightly lower than that of the sand casting method (55.690 BHN). In contrast, sand casting resulted in a coarser microstructure, less uniform copper distribution, and the presence of microsegregation and porosity, which negatively affected the mechanical performance.In conclusion, the permanent mold casting method offers superior performance in producing Al-Cu alloy components for motorcycle roller housings, particularly in terms of wear resistance, impact strength, and microstructural integrity.