Stability of the B19 martensite in rapidly solidified Ti–Ni–Cu alloys

Stabilization of the B19 martensite by rapid solidification in a Ti–45Ni–5Cu (at.%) alloy has been investigated by means of differential scanning calorimetry and transmission electron microscopy. Rapid solidification process induced the B2–B19 transformation prior to formation of the B19′ martensite, and thus the two-stage B2–B19–B19′ transformation occurred in as-spun Ti–45Ni–5Cu alloy ribbons. Inducement of the B19 martensite was ascribed to the formation of Ti2Ni particles coherent with the B2 matrix. With increasing Ti content from 49 to 51 at.%, the temperature range where the B19 martensite exists was expanded from 7 to 25 K, which was attributed to an increase in volume fraction of Ti2Ni particles from 10 to 55% and a decrease in the size from 16 to 5 nm.