Powder Metallurgy Synthesis of Heusler Alloys: Effects of Process Parameters

Riaz Ahamed; Reza Ghomashchi; Zonghan Xie; Lei Chen

doi:10.3390/ma12101596

Powder Metallurgy Synthesis of Heusler Alloys: Effects of Process Parameters

Materials (Basel). 2019 May 15;12(10):1596. doi: 10.3390/ma12101596.

Authors

Riaz Ahamed¹, Reza Ghomashchi², Zonghan Xie³, Lei Chen⁴

Affiliations

¹ School of Mechanical Engineering, University of Adelaide, Adelaide, SA 5005, Australia. riazahamed.ahamedkhan@adelaide.edu.au.
² School of Mechanical Engineering, University of Adelaide, Adelaide, SA 5005, Australia. reza.ghomashchi@adelaide.edu.au.
³ School of Mechanical Engineering, University of Adelaide, Adelaide, SA 5005, Australia. zonghan.xie@adelaide.edu.au.
⁴ School of Mechanical Engineering, University of Adelaide, Adelaide, SA 5005, Australia. lei.chen@adelaide.edu.au.

Abstract

Ni₄₅Co₅Mn₄₀Sn₁₀ Heusler alloy was fabricated with elemental powders, using a powder processing route of press and sinter, in place of vacuum induction melting or arc melting route. The effects of process parameters, such as compaction load, sintering time, and temperature, on the transformation characteristics and microstructures of the alloy were investigated. While the effect of compaction pressure was not significant, those of sintering time and temperature are important in causing or annulling martensitic transformation, which is characteristic of Heusler alloys. The processing condition of 1050 °C/24 h was identified to be favorable in producing ferromagnetic Heusler alloy. Longer durations of sintering resulted in an increased γ-phase fraction, which acts as an impediment to the structural transformation.

Keywords: Heusler alloy; martensite; microstructure; powder processing; process parameters.