Properties of porous NiTi SMAs fabricated by low pressure sintering

Currently, methods commonly used for producing porous NiTi shape memory alloys (SMAs) from elemental powders include conventional sintering(CS), Self-propagating high temperature synthesis (SHS), Hot Isostatic Pressing (HIP) and Capsule-free hot isostatic pressing (CF-HIP). CS requires long heating times and the shape and size of the pore cannot be controlled easily. One of the difficulties of using SHS is the inability to control the repeatability of the sintering process. On the other hand, the HIP and CF-HIP processes require high pressure and high temperature equipments thus making the manufacturing process expensive. The present work focuses on the fabrication and characterization of porous NiTi SMAs produced from elemental powders use Low Pressure Sintering (LPS) . By controlling the processing parameters, such as, the sintering time of LPS, the porous NiTi SMAs resulted in round pore shape and homogeneous pore distribution. The porous NiTi SMAs produced by LPS also exhibits good mechanical properties, such as superior superelasticity and a higher compressive strength. Copyright © 2008 ASM International® All rights reserved.