In-situ 14H-LPSO reinforced GW93 alloy prepared from the recycling of discard components by rapid-solidification plus hot press sintering technique

Abstract

Rapid-solidification (RS) plus hot press sintering (HPS) technique is adopted to achieve the efficient recovery of discard Mg-Gd-Y-Zn-Zr alloy parts. Ribbons are prepared by melt-spinning method from the discard fragments of GW93 components possess high uniform distribution of Gd and Y elements with a high solubility in α-Mg matrix, fine Mg3(Gd, Y) intermetallic particles and α-Mg grains (1.28 μm). Then the ribbons are consolidated through HPS. Results showed that the precipitates in the sample sintered at 500 °C contains fine Mg5(Gd, Y) particles and 14H-LPSO, and the volume fraction of 14H-LPSO is as high as 34.8%. Elevating the sintering temperature to 550 °C only results in the formation of Mg5(Gd, Y) particles. The sample sintered at 500 °C demonstrates excellent mechanical strength with a high ultimate compressive strength (429.76 MPa), yield strength (194.13 MPa) and compressive strain (23.94%), which are 14.85%, 44.89% and 36.51% higher as compared to those of the sample sintered at 550 °C. It is the 14H-LPSO which has high elastic moduli, Vickers hardness and coherent interface with α-Mg matrix, fine grains, the less oxidation defects at the bonding interface that contribute to enhancement of mechanical strength. The RS plus HPS technique is a viable approach for recycling the discard Mg-RE alloy parts and fabricate Mg alloy with superior mechanical properties.