RELATION OF PHASE TRANSITION WITH K_(1c) FOR CERAMIC MATERIALS OF BaTiO_3,VO_2 AND BiSrCaCu_2O_y
BaTiO_3,VO_2和 BiSrCaCu_2O_y 陶瓷相变与 K_(1c)的关系

Values of plane strain fracture toughess,for polycrystalline BaTiO_3,VO_2 and BiSrCaCu_2O_y have been measured by using three-point bending method aboveand below their phase transition temperatures.It is shown that toughnesss of the materialswill be improved below the phase transition temperatures if there remain some high tem-perature phases.