The microstructural evolution of a pre-alloyed AZ91 magnesium alloy powder through high-energy milling and subsequent isothermal annealing

• Published in: Materials letters Vol. 98; pp. 182 - 185
• Main Authors: Taleghani, M.A. Jabbari, Torralba, J.M.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-05-2013
• Subjects: alloys; annealing; AZ91 magnesium alloy; High-energy milling; Isothermal annealing; magnesium; Microstructural evolution; microstructure; milling; Pre-alloyed powder; temperature; High-energy milling; Microstructural evolution; Pre-alloyed powder; Isothermal annealing; AZ91 magnesium alloy
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/j.matlet.2013.02.052

This study analyzed the effect of high-energy milling (HEM) and subsequent isothermal annealing on the microstructural characteristics of a pre-alloyed AZ91 Mg alloy powder. To this end, the mentioned powder was milled for 14h using a horizontal attritor. Then, the mechanically milled powder was isothermally annealed at temperatures ranging from 200°C to 500°C for 1h up to 4h in an Ar atmosphere. HEM caused the β-Mg17Al12 phase present in the microstructure of AZ91 powder particles to dissolve into their α-Mg solid solution matrix. In addition, the crystallite size of the α-Mg phase decreased to 25nm through HEM. In contrast to the annealing time, the temperature of isothermal annealing had a significant effect on the microstructural features of the mechanically milled AZ91 powder.
► A nanostructured AZ91 Mg alloy was prepared by high-energy milling. ► The crystallite size of the milled AZ91 powder was measured to be 25nm. ► The nanostructured AZ91 alloy was annealed at different temperatures for up to 4h. ► Processed AZ91 Mg alloy presented a good thermal stability against grain growth.