Processing of Light-Weight Shape Memory Alloys Using Spark Plasma Sintering

Abstract

Light-weight shape memory alloy (SMA) materials can have important applications in aerospace industry. Considerable research effort has been directed to developing such multifunctional materials which can be used in smart structures. Light weigh, which is crucial in aerospace applications, can be achieved by making the material in porous form, or by forming composites of SMAs with low mass density materials. Porous SMAs have been fabricated using conventional sintering, hot isostatic press, and self-propagating high temperature synthesis. The first two methods require long processing time, and the materials produced by self-propagating high temperature synthesis have been found to have low toughness. These processing techniques also suffer from the difficulty of controlling the formation of inter-metallic phases, which deteriorate the shape memory effect of the material. A new processing method, spark plasma sintering, is being developed to produce light-weight high-quality porous SMAs from elemental Ni, Ti, and TiH2 powders, as well as light-weight carbon nanotube composites of SMA matrix. The primary goal is to produce materials with low apparent density, clear shape memory effect, and good mechanical properties.