基于序列图像重构的Al_2O_3/(W,Ti)C纳米复合陶瓷材料抗弯强度预测

Bending Strength Prediction of Al_2O_3 /(W,Ti)C Ceramic Nanocomposite Based on Sequence Image Reconstruction Method

针对考虑细观构造特性的纳米复合陶瓷材料宏观强度预测问题,开发基于序列图像的多相材料细观构造有限元重构方法,建立可以准确反映Al2O3/(W,Ti)C纳米复合陶瓷材料细观构造的三维有限元模型,并且利用统一强度理论建立可考虑线性硬化的弹塑性本构模型,编写用于强度预测的有限元程序。假设各组分相均为刚塑性材料,考虑统一强度理论各种退化模型(b=0,b=0.5,b=1.0)数值预测材料宏观抗弯强度的上下限,并且发现计算模型参数b=0.5时所得结果与试验结果吻合很好。假设材料增强相具有硬化效应,研究它对材料宏观抗弯强度的影响。研究材料组分相体积分数比与Al2O3/(W,Ti)C纳米复合陶瓷材料宏观抗弯强度之间的关系,为今后材料设计、优化提供参考。

To consider the influence of material＇s microstructure on macro-bending strength of A12O3/（W, Ti）C ceramic composite, a method for automatically reconstruct FE mesh models of materials is developed based on X-ray tomography image, and a calculation program considering the material＇s strain-hardening for strength prediction is complied by using unified strength theory（UST）. Then the upper and lower limit of the bending strength of AI2O3/（W, Ti）C ceramic composite is forecasted based on the rigid-plastic assumption with UST. The predicted strength is proved to be accurate compared with the experimental result when the parameter b, in UST, is chosen to be 0.5. Utilizing linear-hardening elastic-plastic constitutive model based on UST, the relationship between hardening effect of reinforcing phase and macro-bending strength of AI2O3/（W, Ti）C ceramic composite is studied. Considering different volume fraction of compositions in A12O3/（W, Ti）C, bending strength of A12O3/（W, Ti）C ceramic nano-composite is forecast, which can be used for reference of research and development ofA12O3/（W, Ti）C ceramic composite.