Journal of Materials Research and Technology (Nov 2024)

Effect of cryogenic temperature on the strengthening mechanisms of AZ61 Mg alloy extruded at different temperatures

  • Hafiz Muhammad Rehan Tariq,
  • Umer Masood Chaudry,
  • Joung Sik Suh,
  • Young Min Kim,
  • Tea-Sung Jun

Journal volume & issue
Vol. 33
pp. 335 – 348

Abstract

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This study investigates the influence of extrusion and deformation temperatures on the mechanical properties of the AZ61 Mg alloy. Increasing the extrusion temperature from 300 to 400 °C led to larger grain size and higher basal texture intensity. At 400 °C, the AZ61 alloy exhibited more Al–Mn phases and fewer Mg17Al12 phases, indicating enhanced dissolution of Mg17Al12 in the α-Mg matrix. Uniaxial tensile tests were conducted at room temperature (RT) and cryogenic temperature (CT, −150 °C). Despite grain growth, a higher yield strength (YS) was achieved at higher extrusion temperatures due to the texture-strengthening mechanism. However, during deformation at CT, the higher YS was primarily attributed to the formation of multiple twinning within individual grains, causing twinning interactions. These twin-interacting boundaries create additional barriers to dislocation movement. Notably, the AZ61 sample extruded at 400 °C demonstrated the formation of stacking faults during deformation at CT, with dislocations accumulating around the faults. This contributed to the best strength without compromising ductility in this sample.

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