论文部分内容阅读
运用Voronoi方法建立了反映金属基颗粒增强复合材料(MMCp)微结构的多晶集合体代表性单元(RVE);采用Taylor关系推导了包含颗粒结构尺寸和体积分数参数的位错滑移硬化函数;建立了由300个平均粒度约为20μm的晶粒组成的多晶集合体代表性单元,并对MMCp3.5-5、MMCp3.5-10、MMCp10-5、MMCp10-10四种具有不同粒径和体积分数的铝基SiC颗粒增强复合材料在宏观均匀变形条件下的应力应变响应进行了数值模拟。计算结果表明:复合材料的应力应变模拟曲线与试验曲线吻合得较好,说明所推导的模型和硬化模式能够合理地描述颗粒增强尺度效应的变化趋势;多晶体模型也能够合理地表现复合材料内部应力应变在空间分布上的细观不均匀性。数值模拟结果反映了颗粒增强区承载着较大的载荷份额,而非颗粒存在区(基体)则承受着高达18%的应变,在两个区域的交界处出现了高达310MPa的应力集中,与已有文献试验观测的结果比较吻合。
The representative element (RVE) of polycrystalline aggregates reflecting the microstructure of metal matrix particle reinforced composites (MMCp) was established by Voronoi method. The dislocation slip hardening function was deduced using the Taylor relationship between the particle size distribution and the volume fraction parameters. A representative unit of polycrystalline aggregates composed of 300 grains with an average grain size of about 20μm was established. Four kinds of typical aggregates of MMCp3.5-5, MMCp3.5-10, MMCp10-5 and MMCp10-10 with different particle size And the volume fraction of aluminum-based SiC particle reinforced composites under macroscopic uniform deformation stress-strain response were numerically simulated. The calculated results show that the simulated stress-strain curves of the composites are in good agreement with the experimental curves, indicating that the derived model and the hardening mode can reasonably describe the trend of the particle-scale effect. The polycrystalline model can also reasonably represent the interior of the composites Microscopic inhomogeneity of stress and strain in spatial distribution. The results of the numerical simulation show that the particle-reinforced zone carries a larger load share, whereas the non-particle-bearing zone (matrix) sustains up to 18% of the strain. Stress concentration up to 310 MPa occurs at the junction of the two zones, The results of literature experimental observations are in good agreement.