SHAPE MEMORY PROPERTIES OF NICKEL RICH NI-TI ALLOYS

摘要

Nickel rich binary Ni-Ti alloys have been under study for shape memory and superelastic applications. Two alloys (Ni-45Ti and Ni-48Tiat. percent) have been successfully rolled into thin sheets and characterized. Processing variations can produce alloys hard enough to be used as cutting tools or soft and fully martensitic at room temperature. These compositions offer unique opportunities to manufacture higher strength binary alloys that can be processed in a manner that the austentite start (A_s) and austentite finish (A_f) temperatures can be precisely controlled from -80 deg C to +80 deg C. Bend free recovery testing and differential scanning calorimetry (DSC) data has been used to demonstrate how precisely A_s, A_f, and the difference between A_s and A_f can be controlled.