A novel laser cladding AlMgZnCuErZr alloy: Material genetic design, strengthening andtoughening mechanisms
Yue Wang, Xueting Chen, Youcai Zhang, Jing Liang, Jialu Chen, Changsheng Liu, Mei Wang
Abstract
Aluminum alloy with high strength, toughness, and corrosion resistance is one of the new materials for laser additive manufacturing of lightweight high-speed train brake discs. However, due to the non-equilibrium solidification characteristics during the laser melting process, the commercial Al alloys with high performance and laser formability faces several bottlenecks in alloy composition design and preparation. This paper employs a material genetic design method to develop a novel laser cladding Al14Mg9Zn6Cu2Mn0.5Si0.6Er0.4Zr alloy, which exhibits excellent laser formability and better strength, toughness, and corrosion resistance under an optimized laser energy density of 1157 J/mm3. Specifically, an in-situ generated T-AlMgZnCuZrEr genetic phase with internal cell-like α-Al was first discovered, which significantly improves the properties the alloy. The alloy sample demonstrates a remarkable compressive strength of 663 MPa along with a deformation of 15 %. The compressive strength and deformation product of the laser cladding sample reaches 9.9 GPa%, which is 13.44 % higher than that of the high-strength AlZnMgCu alloy prepared by other subtractive manufacturing processes. The mechanisms of matching strength-toughness and corrosion resistance of the alloy have been elucidated. This study provides a feasible material design and preparation pathway for laser additive manufacturing of high-performance and lightweight Al alloy high-speed train brake discs.