Surface and Subsurface Defects Investigation of Ni-Ti Samples Processed by Different Fabrication Methods

Abstract

The use of Ni-Ti alloy in medical applications gave a great importance for the right composition of this alloy and the method of fabricating this alloy parts. Medical implants should be tested to assure that there are no defects or imperfections included and so no harmful effects could take place. In this study different Ni-Ti alloy composition samples have been fabricated using three different techniques. These techniques are sand casting, powder-sand casting method and sintering method. A comparison between samples made in by each technique was made. Surface and subsurface defects found in these fabricated samples have been investigated using nondestructive techniques. These non-destructive techniques used were die penetrant testing, electromagnetic method and finally samples were inspected using ultrasonic waves. Based on the results of surface and subsurface nondestructive tests used, samples prepared using sand casting were found to have the lowest surface and subsurface defects and so it is highly recommended to fabricate Ni-Ti alloy implants.