Investigation on the Dry Sliding Wear Behavior of LM 25 Alloy Amalgamated with Novel Combination of Modifiers
摘要
LM 25 (hypoeutectic) alloys are commonly used in their cast form for critical applications like engine blocks and pistons, where enhanced wear properties are essential. In this study, LM 25 alloy was combined with 0.1% Al-5Ti-B as a grain refiner and various amounts of modifiers, including potassium (K) and cerium oxide (CeO2). The sand-cast samples were subsequently heat-treated (HT). The hardness, tensile strength and wear properties of all the castings were evaluated. The alloy containing 0.1 wt.% Al-5Ti-B, 2 wt.% K and 0.5 wt.% CeO2 achieved a maximum hardness of 71.13 HV in the as-cast state and 89.63 HV after HT. This composition also showed a 26.5% increase in tensile strength in the as-cast condition and a 38.4% increase after HT, compared to the base alloy. The wear rate for this sample was 4.467 × 10−5 and 1.787 × 10−5 g/m under as-cast and HT conditions, respectively. The wear rate decreased by 44 and 78% compared to the base alloy without additives. The significant improvements in the mechanical and wear properties of this alloy were attributed to enhanced microstructural features, such as reduced grain size and secondary dendrite arm spacing, which resulted from the addition of the grain refiner and modifiers to the base LM 25 alloy.