W含量对自蔓延离心熔铸TiB_2-TiC-(Ti,W)C陶瓷组织和性能的影响

Effects of W Content on Microstructure and Properties of TiB_2-TiC-(Ti,W)C Composite Ceramic Prepared by SHS Centrifugal Casting

通过在(Ti+B_4C)体系中引入(WO_3+Al)燃烧体系,进而调整两体系的比例,采用自蔓延离心熔铸工艺成功制备出W系列含量的TiB_2-TiC-(Ti,W)C复合陶瓷。XRD、FESEM和XRD结果显示:陶瓷基体主要由Ti B2、TiC和(Ti,W)C固溶体组成,且随着W含量的增加,(Ti,W)C固溶体体积分数增加,而TiB_2和TiC体积分数减少且晶粒逐渐细化,同时,组织分布趋于均匀。力学性能测试表明,随着W含量的增加,TiB_2-TiC-(Ti,W)C复合陶瓷的相对密度和维氏硬度呈上升趋势,而陶瓷的抗弯曲强度和断裂韧性先增大后减小,在W含量为65%时达到最大值,这是TiB_2作为唯一的增强相体积分数逐渐减少的结果。

By introducing（WO3＋Al） thermites into the（Ti＋B4C） combustion system and adjusting the proportion of the two systems, TiB2-TiC-（Ti,W）C composite ceramics with different W mass fraction were prepared by SHS centrifugal casting. XRD, FESEM and EDS results show that the ceramic matrix is mainly composed of TiB2, TiC and（Ti, W）C. As W content increases, the volume fraction of（Ti, W）C increases, while the volume fraction of TiB2 and TiC decrease, whose grains are refined and distributed uniformly. Mechanical properties tests show that relative density and Vickers hardness of the ceramics rise as the W content increases. However, flexural strength and fracture toughness of the ceramics first increase and then decrease, which achieve maxima when the W content is 65%. This is due to the decrease in volume fraction of TiB2 platelet which is the unique reinforced phase of the TiB2-TiC-（Ti, W）C composite ceramic.