DETERMINATION OF HIGH-TEMPERATURE DEFORMATION MECHANISM IN SOLUTION-HARDENED ALLOYS BY ELECTRIC RESISTIVITY MEASUREMENT

It has been examined whether the macroscopic electric resistivity that reflects the microscopic internal structure is applicable as the disc rimination method of the change of high-temperature deformation mechan ism with the increase of strain-rate in solution-hardened alloys. When specimens were held at 473 K after introducing dislocations by deform ation at room temperature, the resistivity decreased rapidly in a shor t time, suggesting that the decrease should include the effect of solu te atmosphere formation around dislocations. When specimens were defor med by tension at 573 K with various strain rates and rapidly cooled, the resistivity measured at room temperature and at 77 K depended on t he flow stress, and the dependence reversed at the breakaway stress of dislocation from their solute atmospheres, Changes in resistivity are discussed relating to the decrease due to atmosphere formation and th e increase due to the increase of dislocation density.