烧结温度对Mo-10Si-8B-0.6%La2O3合金组织与性能的影响

Effect of sintering temperature on microstructure and properties of Mo-10Si-8B-0. 6%La2O3 alloy

采用机械合金化结合热压烧结技术分别在1400、1500、1600和1700℃下制备Mo-10Si-8B-0.6%La2O3合金,研究了不同烧结温度对合金微观组织和力学性能的影响。结果表明,随着烧结温度的升高,合金内金属间化合物Mo3Si相和Mo5Si B2相含量增多,导致合金的韧性降低,强度升高,但Mo3Si和Mo5Si B2相弥散分布于α-Mo基体中同时也能起到细化晶粒尺寸的作用,从而提高合金的力学性能。烧结温度为1400℃时,合金中α-Mo含量最多,金属间化合物含量较少,此时合金的室温抗弯强度最高,达到238 MPa,但高温压缩强度仅为2247 MPa;当烧结温度为1700℃时,合金中的金属间化合物相含量达到最高值,此时合金的高温压缩强度为2485 MPa,室温抗弯强度则低至173 MPa。

Mo-10Si-8B-0.6%La2O3alloys were prepared at 1400℃,1500℃,1600℃and 1700℃by mechanical alloying and HPS（hot pressing sintering）.The effect of different sintering temperatures on microstructure and mechanical properties of the alloys was studied.The result shows that the content of intermetallic compounds Mo3Si and Mo5Si B2in the alloy grows with the increase of the sintering temperature,which leading to the decrease of toughness and the increase of strength.At the same time,the mechanical properties of the alloy can also be improved by the finer grain size of the matrix that caused by the dispersion of Mo3Si and Mo5Si B2.When the sintering temperature is 1400℃,the alloy has the highest content of Mo and the minimum content of Mo3Si and Mo5Si B2,the bending strength of the alloy at room temperature reaches a maximum of 238 MPa,and the high temperature compressive strength is only 2247 MPa.When the sintering temperature rises to 1700℃,the content of Mo3Si and Mo5Si B2in the alloy reaches its highest value,the compressive strength at high temperature is 2485 MPa and the bending strength at room temperature is only 173 MPa.