材料期刊网

研究了动态应变时效和形变孪晶对具有低堆垛层错能的面心立方合金H68黄铜(Cu-32wt-%Zn)拉伸时机械性能的影响.试验是在196—623K温度范围内进行的,应变速率为4.9 x 10~(-4)s~(-1),平均晶粒尺寸为0.05mm.结果表明,该合金在不同温度下静拉伸,其最大均匀应变量,面缩率及形变孪晶体积分数,均以相似的规律,随温度的降低而升高,且在某一定的温度区间,出现一个加工硬化的平台.本试验的另一重要结果是,形变李晶对机械性能的影响,可延续到400K以上,和动态应变时效的作用有一定的重迭.因此,在某一温度区间(如从333—400K),材料机械性能的改变,应是这两种因素综合作用的结果.

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.