Fabrication of porous samples from a high-temperature Cu–Al–Ni–Mn–Nb shape memory alloy by freeze-drying and partial sintering

Abstract

Shape memory alloys (SMAs) find important applications in many fields, including the biomedical, aerospace, and civil construction industries. The increasing interest in these materials arises from their mechanical properties such as shape memory effect, superelasticity, and damping capacity. In this work, porous samples of a Cu–Al–Ni–Mn–Nb alloy were successfully fabricated. It is the first time that porous samples of this alloy are obtained by freeze-drying and partial sintering. The SMA powder was initially mixed with deionized water, citric acid, and poly(vinyl alcohol). After freezing the prepared suspensions on a cold finger, the as-obtained ice crystals were removed by freeze-drying. The green bodies were subsequently heat-treated at 980 °C for 6 h and quenched to room temperature under argon flow. β1’ martensite was the major phase observed in the fabricated scaffolds. It was observed that both the structural properties and damping capacity of the obtained samples depend on the size of the particles used for preparing them. The prepared scaffolds showed interesting damping properties in the martensitic field, which could allow their use in high-temperature applications.

Keywords

• Shape-memory alloy
• Porous materials
• Freeze-drying
• Partial sintering
• Structural characterization
• Damping