Effect of loading pressure on mechanical properties and interface characteristics of 7056 Al alloy particle reinforced Zr-Al-Ni-Cu bulk metallic glass matrix composite prepared by spark plasma sintering

摘要

In this work, the particle-reinforced 7056 Al alloy/ Zr-Al-Ni-Cu metallic glass composites were successfully prepared by spark plasma sintering (SPS) combined with gas atomization at different loading pressures (45 and 400 MPa). No crystallization was observed throughout the composite and 7056 Al alloy particles were uniformly distributed in the glassy matrix. Due to enhanced densification, higher loading pressure (400 MPa) greatly increased the relative density of the composite from 95% to over 98% and its room-temperature compressive strength. When volume fraction of Al alloy was less than 10 vol%, the strength of the composite was higher than that of pure monolithic BMG obtained by SPS, and its plasticity was also improved. With the higher content of Al alloy, the plasticity of the composite continued to increase, but its strength decreased significantly. With the higher volume fraction of Al alloy (>= 30 vol%), yield strength of the composites was accurately described by the iso-stress model. Interface characteristics were investigated by scanning electron microscopy (SEM), nanoindentation and high-resolution transmission electron microscopy (HRTEM). The increase in loading pressure from 45 to 400 MPa caused glassy matrix and Al alloy reinforcement to bond each other more tightly and destroyed the oxide layer at the interface, resulting in an effective increase in the bonding strength of the two-phase interface. A transition layer (similar to 15 nm) occurred at the interface, and some elements such as Zr, Mg and Zn diffused into the interface between glassy matrix and Al alloy particle. (C) 2019 Elsevier B.V. All rights reserved.