室温時効したAl-ZnかMg合金の冷間圧延による比抵抗減少

抄録

Unitended aging time after room temperature (R. T.) rolling was shortened up to 5s by reciprocal rolling of letter "U" shaped specimen using hand-droven reversing mill. Size factor after rolling was estimated assuming same resistivity for first and second solution treatment. Application of this method to several Al-Zn-Mg alloys makes observable the decrease of specific resistivity by the R. T. rolling, similarly as that by tensile deformation at 78K. The maximum decrement of resistivity ranges 4.2-13% of the resistivity increment by aging before the deformation. Generally, the resistivity decrement by deformation is large in high concentration alloys and becomes larger in the alloy of higher Zn concentration. Aging after deformation is accelerated in initial stage with degree of deformation by both R. T. rolling and 78K elongation, but is decelerated rapidly in later stage of aging.