T300/LD2热循环时产生滞后环原因及改善方法探讨

THE STUDY ON THE HYSTERESIS LOOP OF T300/LD2 AND IT'S IMPROVING

T300/LD2复合材料在热循环时产生滞后环并留下很大的残留应变。本文对T300/LD2试样在热循环时产生滞后环和残留应变的原因进行分析和探讨。实验结果表明,基体在热循环时大量的塑性变形是产生滞后环和残留应变的主要原因,并通过在界面预设不同应力和缩短热循环温度区间来研究界面应力状态和热循环温度区间跟热循环时滞后环和残留应变之间的关系。提出了改善残留应变和滞后的方法(1)尽量减少复合材料的使用环境中的温度变化,(2)根据材料的使用环境,经过各种预处理使复合材料在工作时基体处于弹性变形状态,(3)提高基体的屈服强 度。

This paper studied the reasons of causing hysteresis loops and thermal strains of T300/LD2 when it is in thermal cycling. Experiment results indicated that the large plasticity of the matrix causes the thermal residual strains and hysteresis loops. It was also analyzed that the relations among the stress states of interfaces, the tomporaturc ranges of thermal cycling and the thermal residual strains, A suggestion was put forward to improve the hysteresis and residual strain, which contains(1) minimizing the temperature ranges of working environment of composites(2) making the matrix elastic under the working conditions and (3)increasing the yield stress of matrix.