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

Abstract

In this study, a multilayer laser-cladding method was used to increase the Si content in a hypereutectic Al-Si alloy laser cladding. One-, two-, and three-layer claddings were produced by printing Si powder paste on A1050 aluminum surfaces using 180-, 210-, and 250-㎛-thick plastic tape, respectively, and then irradiating laser pulses over them. The two-and three-layer claddings were produced by printing on the one-and two-layer cladding surfaces, respectively. The one-layer cladding had a thickness of approximately 190 ㎛ and was uniform and defectless. The cladding had a chemical composition of Al-20.2 wt.% Si and had a fine eutectic Al-Si microstructure in most regions. By contrast, the two-layer cladding had a thickness of approximately 250 ㎛ and exhibited many pores and some cracks. The cladding had a chemical composition of Al-60.5 wt.% Si and a hypereutectic Al-Si microstructure with many coarse primary Si particles. Finally, the three-layer cladding had a thickness of approximately 280 ㎛ and exhibited many large pores and a few large cracks. The cladding had a chemical composition of Al-72.6 wt.% Si and a hypereutectic Al-Si microstructure with very coarse primary Si particles. Block-on-roll wear tests were then performed on the claddings. The weight losses in the one-, two-, and three-layer claddings following the wear test were 5.5, 7.7, and 8.3 mg, respectively.