Abstract
The effects of rare earth element Sm on the microstructure, mechanical properties, and shape memory effect of the high temperature shape memory alloy, Cu-13.0Al-4.0Ni-xSm (x = 0, 0.2 and 0.5) (wt.%), are studied in this work. The results show that the Sm addition reduces the grain size of the Cu-13.0Al-4.0Ni alloy from millimeters to hundreds of microns. The microstructure of the Cu-13.0Al-4.0Ni-xSm alloys are composed of 18R and a face-centered cubic Sm-rich phase at room temperature. In addition, because the addition of the Sm element enhances the fine-grain strengthening effect, the mechanical properties and the shape memory effect of the Cu-13.0Al-4.0Ni alloy were greatly improved. When x = 0.5, the compressive fracture stress and the compressive fracture strain increased from 580 MPa, 10.5% to 1021 MPa, 14.8%, respectively. When the pre-strain is 10%, a reversible strain of 6.3% can be obtained for the Cu-13.0Al-4.0Ni-0.2Sm alloy.
Highlights
Shape memory alloys (SMAs) are functional metal materials
More and more studies are focusing on the application of SMAs at higher temperatures, and in particular, high temperature shape memory alloys (HTSMAs) have the potential to be used as solid-state actuators in high temperature fields of aerospace, nuclear power, fire, oil, and gas exploration [8,9,10,11,12,13,14]
It can be seen that the grain size is decreased obviously with the Sm content increased
Summary
Due to its reversible thermoelastic martensitic transformation [1,2,3], SMAs have very special mechanical properties, such as hyperelasticity and shape memory effect (SME), making them suitable for sensing and drive applications [4]. More and more studies are focusing on the application of SMAs at higher temperatures, and in particular, high temperature shape memory alloys (HTSMAs) have the potential to be used as solid-state actuators in high temperature fields of aerospace, nuclear power, fire, oil, and gas exploration [8,9,10,11,12,13,14]. The alloying method has the characteristic of simple equipment, and so the addition of the fourth element is considered to be an effective method to improve the mechanical properties of Cu-Al-Ni SMAs, with simple operation and convenient production [22,23,24,25]
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