Laser melting deposition of Mn-Cu-based alloy: Microstructure, mechanical properties and damping capacities

Mn-Cu-based alloys are promising structural materials for noise and vibration reduction, and Mn-Cu-based alloys with medium Mn content offer significant advantages in formability and corrosion resistance. The preparation of Mn-Cu-based alloys using traditional processes has disadvantages such as the ease of defects and long preparation cycles. Laser melting deposition was employed to fabricate the Mn-36.53Cu-4.30Al-3.07Fe-2.46Ni-0.64Zn (wt. %) alloy thin wall sample, and the microstructure, mechanical characteristics, and damping capacity of the as-deposited samples were investigated. The microstructure of the as-deposited alloy revealed randomly dispersed fine γ-(Mn, Cu) dendrites and a small quantity of α-Mn phase across different sections. The as-deposited samples along the scanning direction (AD-S) exhibited an ultimate tensile strength (UTS) of 584±6 MPa, while those along the deposition direction (AD-D) showed a UTS of 578±6 MPa. The elongation of AD-S samples measured at 40±0%, and for AD-D samples, it was 31±1%. At ambient temperature, the as-deposited alloy displayed high damping properties with a frequency of 1 Hz and a strain amplitude ranging from 30 to 100 × 10−6. The findings contribute to the practical applications of Mn-Cu-based alloys, particularly those with a medium Mn concentration.