Study on the Improvement of Brazeability for Copper-Aluminum Dissimilar Materials Joint

J. Ocean Eng. Technol. 2001;15(3):49-57.

구리-알루미늄 이종재료의 브레이징 특성 향상에 관한 연구

정호신,배동수,고성우

부경대학교 재료공학부,동의대학교 신소재공학과,울산기능대학 생산자동화과

Keywords: Brazing, Filler metal, Dissimilar materials, Brazed joint, Brazing temperature, Metallic compound, Solidus temperature

핵심용어: 브레이징, 삽입재, 이종재료, 접합부, 브레이징 온도, 금속간 화합물, 고상선 온도

Abstract

One of the most important considerations to braze Cu-Al dissimilar materials is control of brittle metallic compound which makes it difficult to obtain a sound brazed joint. Nowdays, several attempts were made to control the metallic compound. But effective method for controlling metallic compound was not established. In this point of view, commercially pure aluminum and copper were used as base metal and Al-Si-X and Zn-Al-X alloy systems were developed as filler metal. Brazing was carried out to find optimum conditions for Cu-Al dissimilar joint. The results obtained in this study were summarized as follows: 1) The joint brazed by Al-Si-X filler metal showed good brazeability and mechanical properties. The tensile strength of the joint brazed over solidus temperature was more than 90% of Al base metal. Especially, the joint brazed at liquidus temperature was fractured in the Al base metal. 2) Fluorides fluxes(a mixture of potassium fluoro-aluminates) were used to improve surface cleanliness of base metal and wettability of Al-Si-X filler metal. It was melted at the temperature about 1$0^{circ}C$ lower than that of the filler metal, and made appropriate brazing environment. Therefore, it could be a proper selection as flux.