EFFECTS OF DYNAMIC STRAIN-AGING AND DEFORMATION TWINNING ON THE MECHANICAL PROPERTIES OF BRASS H68

The effects of dynamic strain-aging and deformation twinning on the tensileproperties in a low stacking fault energy fcc alloy,brass H68(Cu-32wt-%Zn),were investigated.The experiments were carried out at 196 to 623 K with a strainrate of 4.9×10~(-4)s~(-1).The average grain size is 0.05mm.The results showed thatfor this alloy,the maximum uniform strain,the reduction of area and the twin-ned volume fraction at different temperature are all increasing by lowering tem-perature in the similar manner.It was also found that there is an evident work-hardening peak of this material in a certain temperature region.Another impor-tant result of this investigation is that the effects of deformation twinning onthe mechanical properties extend about 100 degrees above room temperature andthat therefore an overlap of the influences of deformation twinning and dynamicstrain-aging was obtained.It is believed that the changes of mechanical propertiesof this alloy in a certain temperature range,say from 333 to 400 K,is becauseof the combined influence of those two factors.