SiC/Al梯度功能材料燃气舵样件的应变测试

STRAIN TESTING OF SiC/Al FUNCTIONALLY GRADIENT MATERIAL GAS HELM SAMPLE

SiC/Al梯度功能材料的各梯度层由不同体积浓度的陶瓷和金属组成,由于材料组分梯度变化,克服了双材料界面的应力突变问题,从而能获得优异的使用性能。文中用激光云纹干涉法,对具有四个梯度层的SiC/Al梯度功能材料航空燃气舵梯形样件在三种工况下进行实验研究。通过实验采集试件随各载荷变化的位移场云纹图,根据位移与条纹级数的关系以及小变形条件下应变与条纹级数关系式,获得样件的应变分布。通过实验结果与文献对比分析,在有关梯度功能材料样件的热缓和效应和热分散效应方面取得一致结论;同时,就实验获得的应变测量结果,讨论梯度功能材料的物性变化规律;另外,文中尝试建立一种简化的样件计算模型,采用该模型所得计算结果与实验数据较一致。

SiC/Al functionally gradient rnaterials（FGM） have gradient layers made up of different volume concentration ceramic and metal. The large stress changes in the interface of bi-material are avoided in functionally gradient materials because of the gradient of the material property, thus FMG materials have excellent application performance. The laser Moire interferometry is applied to study the mechanical behaviors of FGM gas helm sample under three engineering conditions, where the experimental means is based on front-wave interferometry principle. A comparison between experimental Moire fringes and conclusions in references leads to an agreement about the effects of both thermal relaxation and thermal disperse in a FGM compound structure; meanwhile this work discusses the material property change tendency in a FGM trapezoid sample; in addition, a simplified model of trapezoid FGM sample is built, from which the strain resuits of the first two engineering conditions match well with experimental strains.