Work hardening in ordered alloys with special reference to β-phase AgMg alloys

The jog theory of work hardening (Hirsch 1960) has been used to examine the effect of temperature on the work-hardening behaviour of ordered alloys, particularly the temperature Tc at which the change in diffusion controlled flow occurs. The analysis shows that provided vacancies allow the destruction of the anti-phase boundary sandwich normally formed by moving jogs, then T c will occur at a lower fraction of the melting temperature for ordered alloys than for pure metals and disordered alloys. A linear relation between 1/T c and ln ε is also expected. Support for the analysis has been obtained from experimental work on β-phase silver—magnesium alloys. A lower value of T c is thought to be a general feature of ordered alloys and responsible for the change of slope observed in graphs of hardness as a function of temperature in many intermetallic compounds.