Ti-Ni alloy articles having a property of reversible shape memory and a method of making the same

摘要

A reversible shape memory (R.S.M.) article of Ti-Ni alloy containing excess Ni over the stoichiometric composition, such as containing 50.3-53. 0 at. % Ni which has a dual phase structure of a TiNi compound phase and a precipitated Ni rich compounds phase and the improved R.S.M. property wherein the different two shapes are recovered by thermal cycles between two temperatures sufficient higher and lower than the martensitic transformation temperature (Ms). The alloy prepared by the melting method is heat-treated at 600° C. or more to be made into a single phase of TiNi compound after being worked into a strip plate, and the plate is fixedly wound on a pipe and aged at 300° C.- 600° C. for one or more hours, whereby the article having the R.S.M. property with a large amount of shape change by thermal cycles can be obtained.