Realization of High-performance Materials Through Control of Mezoscopic Structure of Materials

1.通过在77K ~ 373K环境温度下的精密拉伸试验，建立了马氏体相变随应变速率、温度和外加应力系统变化的本构方程。利用所建立的本构方程，建立了TRIP钢变形行为预测的计算策略3。通过计算预测77K和293K的应力-应变关系对比，验证了本构方程预测变形行为宏观性质的有效性。计算预测了77K拉伸变形环形缺口试样上马氏体相的局部分布，并与显微硬度测试装置设计的实验结果进行了比较。结果吻合良好，验证了本文计算策略的有效性。对不带环形缺口和带环形缺口的TRIP钢在77K单轴拉伸下的变形行为进行了计算模拟。通过与实验结果的比较，验证了计算结果的准确性。采用一种逆向方法来控制变形过程，以实现材料力学性能的改善。

1.By means of precise tension tests conducted at the environmental temperatures of 77K to 373K, the constitutive equation that models for martensitic transformation depending on strain rate, temperature and applied stress system, was established.2.The computational strategy for the prediction of the deformation behavior of TRIP steels was then developed using the established constitutive equation3.Through comparison between the computationally predicted stress-strain relation for 77K and 293K, the validity of the proposed constitutive equation in predicting macroscopic nature of deformation behavior was verified. The local distribution of the martensitic phase over the ringed-notched specimen deformed under tension at 77K was predicted computationally and compared with the values obtained by a specially arranged experimental procedure using the micro-hardness testing device. The good correspondence between the two results confirms the validity of the present computational strategy.4.A computational simulation of the deformation behavior of TRIP steel bars without/with the ringed notch under uniaxial tension at 77K was performed. The accuracy of the computational results was verified through the comparison against the experimental results.5.A sort of inverse method was used to control the deformation processes to realize the improvement of the mechanical property of materials.