Enhanced mechanical properties of Fe-based hardfacing alloy with Al additions fabricated by laser cladding
Zhuotao Hu, Dabin Zhang, Dongsheng Wu, Xiaoqiang Zheng, Jie Sun, Peihao Geng, Ninshu Ma
Abstract
Laser cladding was used to prepare an Al-containing Fe-Cr-C hardfacing alloy layer on a 316 L stainless steel substrate. The effects of Al addition on the elemental distribution, physical phase composition, and properties of the cladding layers were systematically investigated using experimental observations, finite-element simulation, and performance tests. Aluminum promoted the flow and elemental homogenization of the molten pool, leading to a more dispersed carbide distribution. Aluminum increased the thermal conductivity of the material and accelerated the cooling rate of the melt pool, which suppressed the eutectic reaction L → γ + (Fe,Cr) 7 C 3 and promoted the peritectic reaction L + (Fe,Cr) 7 C 3 → γ + (Fe,Cr) 3 C. Consequently, the (Fe,Cr) 7 C 3 content decreased, whereas that of (Fe,Cr) 3 C increased. Aluminum improved the stability of ferrite and promoted its formation. The Al addition resulted in fine-grain, load-transfer, dislocation, and Orowan strengthening, thereby improving the hardness and wear resistance of the Fe-Cr-C hardfacing alloys. Dislocation and Orowan strengthening were the largest contributors, followed by fine-grain and load transfer strengthening.