The effect of silver addition on microstructure and thermal properties of the Cu–10%Al–8%Mn shape memory alloy

Dragan Miroslav Manasijevic,Nada Štrbac,Milan Gorgievski,Duško Minić,Ljubiša Balanović,Milena Premović,Uroš Stamenković,Emi Govorčin Bajsić,Tamara Holjevac Grgurić,Radiša Todorović,Mirko Gojić

doi:10.30544/321

Abstract

The influence of Ag addition on microstructure and thermal properties of the Cu-10%Al–8%Mn alloy was investigated in this work. Two alloys with designed compositions Cu-10%Al–8%Mn and Cu-10%Al–8%Mn-4%Ag (in wt.%) were prepared by induction melting of pure metals. Microstructures of the prepared samples were investigated in the as-cast state, after homogenization annealing and after quenching. The effects of different methods of heat treatment on the microstructure and transformation temperatures of the investigated Cu-10%Al–8%Mn and Cu-10%Al–8%Mn-4%Ag alloys were investigated using SEM-EDS and DSC techniques.It was determined that after induction melting microstructure of the both investigated alloys are primarily composed of martensite and a small amount of α-phase precipitates.Fully martensitic structure in both investigated alloys was obtained after direct quenching from the 850 °C into the ice water. Based on the DSC cooling curves it was determined that two-step martensite transformation for the both investigated alloys occur in the temperature interval from about 30 to -40 °C.

Highlights

IntroductionThe shape memory effect in the Cu-based SMAs is based on martensitic transformation (MT) which is a diffusionless and reversible solid-state phase transformation [2,3,4]
Cu-based shape memory alloys (SMAs) show good shape memory properties, high electrical and thermal conductivity, are easier to produce and process and have lower production cost comparing to Ni-Ti-based SMAs [1, 2].The shape memory effect in the Cu-based SMAs is based on martensitic transformation (MT) which is a diffusionless and reversible solid-state phase transformation [2,3,4]
The microstructure of prepared bulk alloys was investigated in the as-cast state, after homogenization annealing, and after direct quenching into the ice water

Summary

Introduction

The shape memory effect in the Cu-based SMAs is based on martensitic transformation (MT) which is a diffusionless and reversible solid-state phase transformation [2,3,4]. It occurs between the high-temperature austenite phase and the low-temperature martensite phase [3,4]. The martensitic transformation (MT) occurs at a temperature Ms (martensite start) and continues to evolve until a temperature Mf (martensite finish) is reached. During the heating cycle, the reverse transformation (martensite-toaustenite) begins at the temperature As (austenite start) and ends at Af (austenite finish) when the material is fully austenite [2].

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Conclusion