Temperature dependence of elastic constants of some cermet specimens

The te mperat ure dependence of both Young's and shear modulus of four types of cermet specimens, known as " nickel-bonded t itanium carbide," as well as Ni and TiO ha ve been determined by a dyna mic resona nce method.The Young's mo dulus te mpera t ure curves of t he cermets a re cha racterized by a linear decrease from room t emperature until a bo ut 700 to 1,000 °0 .In t his upper te mperature r egion, a n inflect ion in t he relation develops, accompanied by an increase in internal friction .Both these effec ts a re attribu ted to visco us gra in bo undary slip.F or shear modulus, only t he lin ear portion of t he modulus t emper at ure r elatio n was obtained .In t his linear r egion , t he relative decrease i n s hear modulus for t he cermet specimens is greater t ha n t he relative dec rease in Yo ung's modulus for t he sa me type of s pecimen.This mcans t hat Po isson's ratio riscs wit h t emperat ure for t he cermets.------.------2 .