pISSN : 1598-706X / eISSN : 2288-8381
한국주조공학회지 (41권5호 419-433)
Effect of Cu content on Hot Tearing Susceptibility in Al-Si-Cu Aluminum Casting Alloy
Al-Si-Cu 알루미늄 주조 합금의 열간 균열 민감성에 미치는 Cu 함량의 영향
Seung-Hwan Oh*, Chinbat Munkhdelger** and Heon-Joo Kim***,†
*디알 액시온 기술연구소, **부경대학교 대학원 금속공학과, ***부경대학교 금속공학과
Al-Si-Cu alloys benefit from the addition of copper for better hardness and strength through precipitation hardening, which results in remarkably strong alloys. However, the addition of copper expands the solidification range of Al-Si-Cu alloys, and due to this, these alloys become more prone to hot tearing, which is one of the most common and serious fracture phenomena encountered during solidification. The conventional evaluation method of the hot tearing properties of an alloy is a relative and qualitative analysis approach that does not provide quantitative data about this phenomenon. In the present study, the mold itself part of a device developed in Instone et al. was partially modified to obtain more reliable quantitative data pertaining to the hot tearing properties of an Al-Si-Cu casting alloy. To assess the influence of Cu element, four levels of Cu contents were tested (0.5, 1.0, 3.0, and 5.0 wt.%) in the Al-Si-Cu system alloy and the hot tearing properties were evaluated in each case. As the Cu content was increased, the hot tearing strength decreased to 2.26, 1.53, 1.18, and 1.04 MPa, respectively. At the moment hot tearing occurred, the corresponding solid fraction and solidification rate decreased at the same temperature due to the increase in the solid-liquid coexistence range as the Cu content increased. The morphology of the fracture surfaces was changed from dendrites to dendrites covered with residual liquid, and CuAl2 phases were observed in the vicinity of hot tearing.
Hot tearing tendency, Quantitative evaluation of Hot tearing strength, Al-Si-Cu casting alloy and Effect of copper