A Review of Nickel-Titanium Shape Memory Alloys

摘要

Nickel-titanium shape memory alloys based upon the equiatomic intermetallic compoundrnNiTi are used in a wide variety of engineering and biomedical applications. The different NiTirnphases and the origin of the shape memory phenomenon will be described in detail. A variety ofrnexperimental techniques, including differential scanning calorimetry (DSC), thermomechanicalrnanalysis (TMA), and x-ray diffraction, which are commonly employed to characterize thesernalloys, will be discussed at length. The strategies of thermomechanical processing (cold workingrnand heat treatment) and alloy composition modification, which can be utilized to alter therntransformation temperature range and the mechanical properties of these alloys, will bernsummarized. The biocompatibility of nickel-titanium alloys for biomedical applications will berndiscussed critically, and other shape memory alloy systems will be noted. The purpose of thisrnreview presentation is to provide background for subsequent presentations on the use of nickeltitaniumrnalloys for dental and thermal fuse applications.