Fabrication of high-strength AZ80 alloys via multidirectional forging in air with no need of ageing treatment

A high-strength AZ80 alloy (with a tensile strength of 285 MPa, an ultimate strength of 388 MPa, and an elongation of 6.8%) has been fabricated by multidirectional forging (MDF) under air-cooling condition, at an initial temperature of 360 degrees C, with an accumulative strain of 1.8, with no need of ageing treatment. Extensive dynamic precipitation occurs in this sample, which deteriorates the subsequent age-hardening response but still contributes to improving the strength. In addition to the precipitation hardening caused by numerous nano-scale dynamic precipitates, the outstanding strength should also be attributed to the combined effects of other microstructural characteristics resulting from the increase of accumulative strain and decrease of forging temperature. They are 1) grain boundary strengthening by fine recrystallized grains, 2) strain hardening by the large dislocation density, and 3) texture strengthening by the low Schmid factor of basal slip. This paper provides a method of short process to manufacture high-performance large-scale AZ80 components for industrial production. (C) 2019 Elsevier B.V. All rights reserved.