The Effects of Heat Treatment Temperature on Wear Characteristics of Hyper-Eutectic Al-Si Alloy Laser Clad Layer

Abstract

In this study, it was tried to analyze the effects of heat treatment temperature on the microstructure and wear characteristics of the hyper-eutectic Al-Si clad layer. The clad layer was produced by scanning pulsed Nd:YAG laser beam over the Si powder layer printed on the Al050 Al alloy base metal. The chemical composition of the clad layer was analyzed to be Al-20.8%Si. Despite the hyper-eutectic Al-Si composition, the clad layer mainly consisted of the very fine Al-Si eutectic microstructure without primary Si particles. The clad layers were heat-treated at 300 ℃, 400 ℃ and 500 ℃ for 5 hours. The specimen heat-treated at 300 ℃ retained the very fine Al-Si eutectic microstructure, but the continuity of Si particles in the Si network was broken. In the specimen heat-treated at 400 ℃, the Al-Si eutectic microstructure disappeared and fine Si particles were dispersed over the entire area. In the specimen heat-treated at 500 ℃, the melt-solidification traces disappeared and Si particles were grown considerably. The wear weight loss was the lowest in the as-cladded specimen and increased with the increase of heat-treatment temperature. Adhesive wear did not occur in the specimens as-cladded and heat-treated at 300 ℃, but occurred in the specimens heattreated at 400 ℃ and 500 ℃. The very fine Si networks in the Al-Si eutectic microstructure seemed to prevent adhesion of Al substrate to SKD 11 roll surface. Therefore, it was considered that there was no adhesive wear in the specimens which were as-cladded and heat-treated at 300 ℃.

Microstructure and Wear Characteristics of Multilayer Laser-Cladded Hypereutectic Al-Si Alloys

“…Journal of Welding and Joining, Epub ahead of print 2 면이 불균일하거나, 일부 Si 입자들의 미용융이나, 위 치에 따라 조성의 불균일함이 발생하였다 3,4) . 따라서 본 연구에서는 적절한 레이저 출력과 페이스트 층 두께 를 사용하는 반면, 다층 레이저 클래딩에 의해 Si 함량 을 증가시키는 방법을 시도하였다.…”

“…따라서 본 연구에서는 적절한 레이저 출력과 페이스트 층 두께 를 사용하는 반면, 다층 레이저 클래딩에 의해 Si 함량 을 증가시키는 방법을 시도하였다. 3,4) . 각 클래딩에 대해서 단면 미세조직과 성분분석을 위 한 시험편과 마모시험을 위한 시험편을 제작하였다.…”