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钛合金因其优异的强韧性是具有广泛应用背景的轻质材料,但其硬度较低导致耐磨性较差,限制了其作为结构部件的应用。利用Cr3C2,B4C和石墨粉体之间的原位反应,制备了增强相体积分数为10%,TiC和TiB摩尔比1∶1的(TiBw+TiCp)/(Ti-4.0Fe-7.3Mo-xCr)系钛合金基复合材料。混合粉料采用热压烧结方法在20 MPa压力,氩气气氛保护,1300℃条件下保温1 h进行制备。并对复合材料的微观组织结构和力学性能进行了研究。研究表明,通过控制Cr3C2,B4C和C的含量配比,改变以Cr3C2引入的Cr含量对基体和增强相均有影响。复合材料基体由α-Ti和β-Ti两相组成,随Cr3C2引入的Cr含量的增加,β-Ti的含量增加。并且当Cr3C2形式引入的Cr含量由2.2%增加到5.2%时,复合材料的强度得到显著提高,最高可达到908.7 MPa,但其杨氏模量从170 GPa下降到150 GPa,而复合材料的洛氏硬度HRC稳定保持在55,大大高于基体合金。并且Cr3C2的引入也影响着复合材料中原位合成的TiBw与TiCp增强相的分布位置和形态。随由Cr3C2的引入Cr含量增加,TiB晶须的长径比提高,TiC颗粒的粒度细化,对复合材料的强度和韧性起到强化作用。
Titanium is a lightweight material with a wide range of applications due to its excellent toughness, but its low hardness leads to poor wear resistance, limiting its use as a structural component. (TiBw + TiCp) / (Ti-4.0Fe-7.3Mo-xCr) was prepared by in-situ reaction between Cr3C2, B4C and graphite powders with the volume fraction of reinforcing phase of 10% and TiC and TiB molar ratio of 1: ) Department of titanium-based composite materials. The mixed powder was prepared by hot pressing sintering under the pressure of 20 MPa and the protection of argon atmosphere at 1300 ℃ for 1 h. The microstructure and mechanical properties of the composites were studied. The results show that by controlling the content ratio of Cr3C2, B4C and C, changing the content of Cr introduced by Cr3C2 has an impact on the matrix and reinforcement phase. The composite matrix consists of two phases, α-Ti and β-Ti. The content of β-Ti increases with the increase of Cr content introduced by Cr3C2. And when the Cr content introduced by Cr3C2 increased from 2.2% to 5.2%, the strength of the composites was significantly improved up to 908.7 MPa, but the Young’s modulus decreased from 170 GPa to 150 GPa. However, Hardness HRC stable at 55, much higher than the base alloy. In addition, the introduction of Cr3C2 also affects the location and morphology of the TiBw and TiCp reinforcing phases synthesized in-situ in the composites. With the increase of the content of Cr introduced by Cr3C2, the aspect ratio of TiB whisker increases and the grain size of TiC particles is refined, which enhances the strength and toughness of the composites.