Machinability Characteristics of Medical Grade NiTiNOL Shape Memory Alloy

The bone is a functional organ associated with other elements such as vascular systems, cartilage, connective tissues and nervous components. Body movement is possible when these functional organs act together with skeletal muscles. Large bones are more prone to injury in the skeletal system compared to small and medium bones. Injured bones are treated through internal and external fixation of implants. Apart from long bone injury, joint replacement is another prime intervention where the bone is anticipated to host a biomaterial. The regeneration process of a patient's injury depends on the nature of the response of the bone to the implanted biomaterial. The demand for biomaterials is increasing year by year. The field of biomaterials has been on a continuous boom for the last few decades because of the increase in the ageing population and growth in the average weight of people across the globe, apart from common accidents and sports injuries. Heart, blood vessels, shoulders, knees, spine, elbow, ears, hips, dental structures etc., are a few parts of the body in which biomaterials are used as artificial valves, stents, replacement implants and bone plates. More replacements have been registered for hip, knee, spine and dental-related problems. By the end of the next decade, towards 2030, it has been estimated that the number of total knee arthroplasty surgeries is forecasted to grow by 673%, and total hip replacement will increase by 174% compared to the present replacement rate.

The mechanical qualities of the bone deteriorate and are degraded as a result of excessive loading on bones and joints and the lack of a normal biological self-healing process, which causes degenerative illnesses. One of the best solutions to such problems is to use artificial biomaterials as an implant of suitable size and shape, which supports the function of restoring the body movement in the affected joints and compromised structures. No doubt that the replacement surgeries have dwelled, but on the other side, the revision surgeries of knee, hip and spinal implants have been increasing rapidly, which is a matter of concern. These revision surgeries are expensive with a low success rate and, most importantly, painful for the patients. The targets of the present day's researchers are not just to develop appropriate bio-implants but also to select suitable machining techniques and proper procedures to produce such bio-implant alloys, for improving the quality of the implant material to avoid revision surgeries.