Al-Ti合金钎焊SiC陶瓷接头界面微观结构与力学性能

SiC陶瓷具有优异的综合性能, 通过钎焊获得高强度接头是其获得广泛应用的重要前提。研究采用Al-(10, 20, 30, 40)Ti(Ti的名义原子含量10%、20%、30%、40%)系列合金, 在1550 ℃条件下, 对SiC陶瓷进行钎焊30 min。当中间层厚度为~50 μm时, SiC钎焊接头的平均剪切强度处于100~260 MPa范围内。当采用Al-20Ti合金作为钎料时, 随着中间层厚度从~100 μm减小至25 μm, 钎焊接头的平均强度逐渐提高, 且最大强度~315 MPa。同时, 钎焊中间层中(Al)相逐渐减少直至消失, 只留下Al₄C₃、TiC和(Al,Si)₃Ti相。SiC/Al-20Ti/SiC钎焊接头的断裂主要发生在靠近中间层/陶瓷界面位置的陶瓷基体内。

Microstructure and Mechanical Properties of SiC Joint Brazed by Al-Ti Alloys as Filler Metal

SiC ceramic has excellent overall properties, and joining it to other materials with high joint strength is an important issue in the actual applications. Brazing of SiC ceramic to itself was performed using the as-fabricated Al-(10, 20, 30, 40)Ti alloys with nominal Ti concentrations of 10%, 20%, 30%, and 40% at 1550 ℃ × 30 min. The average joint shear strength fluctuates in the range of ~100?260 MPa with the interlayer thickness of ~50 μm. Moreover, the average strength SiC/Al-20Ti/SiC joint is increased markedly with the interlayer thickness decreasing from ~100 to 25 μm, reaching the maximum of ~315 MPa. Meanwhile, the (Al) phase in the interlayers is reduced gradually till disappear with the thinnest brazing interlayer, leaving the Al₄C₃, TiC and (Al,Si)₃Ti phases in the interlayer. The joint fractures of SiC/Al-20Ti/SiC joint mainly occur in the SiC ceramic substrate near the interlayer/ceramic interface.