热压工艺对SiCf/Ti复合材料界面反应层生长影响的数值模拟

提出一个热-力-扩散-反应强耦合相场模型来研究热压烧结制备工艺对连续碳化硅纤维增强钛基复合材料中金属间化合物生长规律的影响。模拟结果表明，在两种不同温度下各个界面反应层(Ti₃SiC₂/Ti₅Si₃C_x/Ti₅Si₃C_x+TiC/TiC)的厚度生长与试验值吻合较好。增大外加压力能促进界面层厚度的生长，但对其中抗拉强度最低的Ti₅Si₃层的生长起显著的抑制作用，同时使各界面反应层由周向拉应力状态逐渐转变为压应力。温度的升高使断裂韧度最大的Ti₃SiC₂层厚度增大，但也使总界面层和Ti₅Si₃层的厚度增加。因此，在制备工艺上适当增加压力并选择合适的温度，得到厚度适宜的界面反应层的同时，尽可能使Ti₅Si₃层变薄和Ti₃Si...

Numerical simulation of effect of hot-pressing process on growth of interfacial reaction layer in SiCf/Ti composites

A phase field model based on strongly coupled thermo-mechano-diffusion-reactional theory was proposed to study the effect of hot-pressing sintering fabrication process on growth law of intermetallic compounds in the continuous silicon carbide fiber reinforced titanium matrix composites. The simulation results show that the thickness of each interface reaction layer is consistent with the experiment at two different temperatures. Further research shows that the applied load can promote the growth of interface reaction layer, but the growth of Ti₅Si₃ layer is significantly inhibited, which has the lowest tensile strength. With the increase of applied load, the circumferential stress changes from tension to compression. The thickness of Ti₃SiC₂ layer increases with temperature rising, which has the maximum fracture toughness, as well as the thickness of the total interface reaction layer and Ti₅Si₃ layer are also increased. Therefore, it is an important way to improve the mechanical properties of SiC_f/Ti composites by properly increasing the pressure and selecting the appropriate temperature in the preparation process to obtain the interface reaction layer with the appropriate thickness, meanwhile, making the Ti₅Si₃ layer thinner and the Ti₃SiC₂ layer thicker as far as possible.