Microstructure and tensile properties of aluminum powder metallurgy alloy prepared by a novel low-pressure sintering

This paper proposed a novel low-pressure sintering process contraposing to characteristics of pre-alloyed aluminum powders and analyzed its feasibility. The low pressure was set to 0.1 MPa in this study. Meanwhile, 0 MPa and 10 MPa were set as control group. With gasatomized 2024 aluminum powders as raw material, the microstructure and tensile properties of specimens sintered under three orders of magnitude of pressure (0 MPa, 0.1 MPa and 10 MPa) at two representative temperatures (525 degrees C and 575 degrees C) were compared. The results showed that it was difficult for pressureless sintering (0 MPa) to densify pre-alloyed aluminum powders, but low-pressure sintering could. As the liquid phase formed at supersolidus temperature was squeezed out, the loss of alloying elements such as Cu and Mg, which would play an important role in subsequent heat treatment, during lowpressure sintering was apparently less than that of 10 MPa. The density of aluminum sintered under 0.1 MPa at 575 degrees C was 2.732 g/cm(3) and the ultimate tensile strength was 228.16 MPa with ductility of 12 %, which achieved a good balance of plasticity and strength. These findings will bring new insights to the industrialization of aluminum powder metallurgy (APM). (C) 2021 The Authors. Published by Elsevier B.V.

Automated summary

This study introduces a novel low-pressure sintering process that can densify pre-alloyed aluminum powders effectively, achieving a good balance between plasticity and strength.