对Asay-Chhabildas(AC)方法、横向应力计方法、压-剪方法和X射线衍射方法等4种高压动态屈服强度测量方法进行了比较,根据应变率的异同,将强度数据分为两类进行比较:X射线衍射方法和压-剪方法获得的强度与AC方法获得的强度Y=2τc进行比较,而横向应力计方法测得的屈服强度与AC方法中的Y=2τH进行比较。通过铝及其合金屈服强度数据的比较分析表明,AC方法、X射线衍射法和压-剪方法测得的强度数据基本一致,但横向应力计法测得的强度远高于AC方法测得的结果(Y=2τH),甚至高于其它3种方法测得的结果 (Y=2τc)。造成横向应力计方法测量结果异常的原因有待进一步研究。与实验数据的比较表明,Steinberg-Cochran-Guinan(SCG)模型过于依赖初始屈服强度,从而导致无法完全反映高压下材料的强度特性,模型有待进一步改进。
The four widely used methods to measure the high-pressure dynamic yield strength of solids, including Asay-Chhabildas (AC) method, lateral stress gauge (LSG) method, pressure-shear (PS) meathod,and X-ray diffraction (XRD) method,were analyzed in the present work. According to the difference of instant strain rate, the yield strengths defined by different methods hereinbefore are divided into two types:one is with high strain-rate,including the data from PS,XRD, as well as Y=2rc from AC method;the another is with zero strain-rate,including the data from LSG, and Y= 2rH from AC method. The yield strengths of various aluminium and its alloys from publications were compared. Results show that the data from PS,XRD,and Y=2rc from AC method are approximately consistent, the data from LSG method, however, are obviously higher than the Y= 2rH from AC method, and even higher than the data with high instant strain-rate. Further work is needed to determine the cause of the abnormal data from LSG method. Results also show that the Steinberg-Cochran-Guinan (SCG) model is strongly affected by the initial yield strength of materials, and a modified model is needed to describe the behavior of yield strength under high pressure or stress.