Phase Formation, Thermal Stability and Mechanical Properties of a Cu-Al-Ni-Mn Shape Memory Alloy Prepared by Selective Laser Melting

Piter Gargarella,Leonardo Albuquerque Basilio,Tobias Gustmann,Cláudio Shyinti Kiminami,Claudemiro Bolfarini,Régis Daniel Cava,Walter José Botta,Jürgen Eckert,Eric Marchezini Mazzer,Simon Pauly

doi:10.1590/1516-1439.338914

Piter Gargarella, Leonardo Albuquerque Basilio + Show 8 more

Open Access

https://doi.org/10.1590/1516-1439.338914

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Abstract

Selective laser melting (SLM) is an additive manufacturing process used to produce parts with complex geometries layer by layer. This rapid solidification method allows fabricating samples in a non-equilibrium state and with refined microstructure. In this work, this method is used to fabricate 3 mm diameter rods of a Cu-based shape memory alloy. The phase formation, thermal stability and mechanical properties were investigated and correlated. Samples with a relative density higher than 92% and without cracks were obtained. A single monoclinic martensitic phase was formed with average grain size ranging between 28 to 36 μm. The samples exhibit a reverse martensitic transformation temperature around 106 ± 2 °C and a large plasticity in compression (around 15±1%) with a typical “double-yielding” behaviour.

Highlights

Selective laser melting (SLM) is a versatile additive manufacturing process
The nominal composition of the powders was confirmed by Materials Research energy-dispersive X-ray spectroscopy (EDX)
The samples exhibited a relative density around 92%, showing a considerable amount of pores as inferred by SEM and X-ray tomography

Summary

Introduction

Selective laser melting (SLM) is a versatile additive manufacturing process. Parts are built layer by layer, which allows customizing their density and obtaining complex shapes[1]. A large number of processing parameters can be varied as laser power, scanning speed, spot size and overlapping of individual tracks (hatching)[1]. This makes necessary to investigate the best combination of parameters in order to produce samples with particular properties, as for example, high density and with a refined microstructure. This method was barely used to fabricate shape memory alloys (SMAs)[2,3]. The Cu-based SMAs have some advantages when compared with traditional TiNi‐based SMAs because they have larger thermal and electrical conductivities, have a lower cost and are easier to process[5]

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