TRANSFORMATION-MISMATCH SUPERPLASTICITY IN REINFORCED AND UNREINFORCED TITANIUM

摘要

Samples of commercial-purity titanium, with and without 10 vol./100 TiC particulates, were thermally cycled about the allotropic transformation temperature of titanium. Thermal ratcheting was small for both unstressed materials. Upon application of an external uniaxial tensile stress, unreinforced titanium exhibited large strain increments, resulting from the biasing by the applied stress of the volume mismatch developed between grains during the transformation. Upon repeated cycling, a strain to fracture of 200/100 was reached, with a strain per cycle proportional to the external stress, in agreement with existing transformation-mismatch superplasticity models.