原位合成(TiB+TiC)/Ti6242基复合材料高温氧化行为

Oxidation Behavior of (TiB+TiC)/Ti6242 Matrix Composites at Elevated Temperature

研究了(TiB+TiC)/Ti6242基复合材料在550℃,600℃和650℃空气中恒温氧化行为。用X射线衍射仪(XRD)和配有能谱仪(EDS)的扫描电子显微镜(SEM)对氧化层表面的相组成、形貌以及氧化层剖面的显微结构进行了分析,并分析了各元素对钛基复合材料氧化动力学行为的影响。结果表明:(TiB+TiC)/Ti6242基复合材料的氧化层由一系列薄层组成;增强体TiB提高抗氧化性优于TiC,加工可以提高其抗氧化性;氧化动力学曲线主要为抛物线类型。

The isothermal oxidation behavior of （TiB＋TiC）/Ti6242 matrix composites at 550℃, 600℃, 650℃ in air was investigated. The reaction products of the oxidation scale were examined by XRD. The surface morphology and cross-section microstructure of the oxidation scale were analyzed by SEM with an attached EDS. Generally, an oxidation scale consisting of two layers, an outward and an inward-growing layer, formed. The addition of aluminum may effectively retard the counter-diffusion of O^2- and Ti^4＋ and, thereby, significantly decreases the scale-growth rate by forming A12O3-rich scale. However, the presence of TiB and TiC reinforcements can also improve oxidation resistance to the TiMMCs. The isothermal oxidation kinetic curves mainly follow parabolic rate law.