碳化硅纤维增强体钛铝基体的原位合成与控制及其动力学解析

Kinetic Analysis and Control of In-situ Synthesis of Titanium-Aluminium Intermetallic Compound Matrix in SiC Fiber Reinforced Composites

摘要:

利用磁控溅射，采用钛靶和铝靶按照一定功率比在SiC纤维表面沉积钛与铝，制备SiC 纤维的Ti-Al基复合先驱丝，按密排堆垛置于包套之中并经热等静压制备碳化硅纤维增强钛铝基试样。通过扫描电镜观察组织形貌，研究热等静压及真空热处理对组织结构、界面反应层的影响，应用XRD与能谱分析，研究磁控溅射功率对原子比的影响以及钛铝原位反应过程中相比例的变化规律，采用差示扫描量热法（DSC，differential scanning calorimetry）对钛铝反应进行动力学分析。结果表明，钛靶与铝靶的溅射功率直接影响钛铝的原子比，TC4和Al靶功率分别为13和4.5 kW/m2，其铝含量为27at%；TC4和Al靶功率分别为13和8.3 kW/m2，其铝含量为49at%。此外，动力学研究表明，Al3Ti是钛铝反应的优先生成相，随着Al的扩散，逐渐形成TiAl、Al2Ti和Ti3Al，但经过Al的充分扩散，其最终形成的稳定相取决于钛铝的原子比，若原子比为1:1，则最终形成TiAl相，且不同原子比区域形成的TiAl、Ti3Al可共存。

Abstract:

Titanium and aluminum were deposited on the SiC fiber by magnetron sputtering according to a certain power ratio. The precursor wires of SiC fibers with Ti-Al matrix were fabricated and then close-packed in the canning. The specimens of SiC fiber reinforced titanium-aluminium intermetallic compound matrix composites were prepared by hot isostatic pressing. Microstructure was observed by SEM, the effects of hot isostatic pressing and vacuum heat treatment on the interfacial layer were analyzed. The influences of magnetron sputtering power on the Ti/Al atomic ratio and variation of phase composition during titanium aluminum in-situ reaction were researched using X-ray diffraction and energy spectrum analysis. Kinetic analysis of Ti-Al reaction was conducted through differential scanning calorimetry. The results show that Ti/Al atomic ratio is directly affected by the sputtering power of Ti and Al targets. When the power of TC4 and Al targets is 13 and 4.5 kW/m2, respectively, the Al content is 27at%; when the power of TC4 and Al targets is 13 and 8.3 kW/m2, respectively, the Al content is 49at%. In addition, studies on kinetics show that Al3Ti is the priority generation phase of Ti-Al in-situ reaction. TiAl, Al2Ti and Ti3Al will be gradually formed with the diffusion of Al. However, after full diffusing of Al, the final stable reaction product depends on Ti/Al atomic ratio. When the Ti/Al atomic ratio is 1:1, TiAl can be obtained, and TiAl and Ti3Al can coexist in the region with the different Ti/Al atomic ratios.