退火工艺对Mo[Si0.9(Al0.04Mg0.06)]2陶瓷性能与结构的影响

Effect of annealing process on properties and structure of Mo[Si0.9(Al0.04Mg0.06)]2 ceramics

针对MoSi2陶瓷材料室温韧性较差,高温强度低等缺点,通过Mg、Al合金化协同增韧MoSi2,采用热压烧结技术制备Mo[Si0.9(Al0.04Mg0.06)]2陶瓷,并通过退火处理工艺对MoSi2复合陶瓷进行处理。着重研究了退火温度(1300、1400、1500和1600℃)、退火时间(3、6、9和12h)对Mo[Si0.9(Al0.04Mg0.06)]2复合陶瓷物相组成、显微结构、致密度以及力学性能的影响。结果表明:退火温度对Mo[Si0.9(Al0.04Mg0.06)]2陶瓷的致密度和硬度影响较大,退火温度为1600℃时,陶瓷试样的致密度达到了98.23%,此时硬度和断裂韧性最大。退火时间对Mo[Si0.9(Al0.04Mg0.06)]2陶瓷的结构与性能也产生一定影响,随着退火时间的延长,试样的致密度、硬度和断裂韧性都有不同程度的增加,当退火时间为12h时,致密度达到了98.71%;当退火时间为9h时,陶瓷试样的力学性能最佳。

In order to overcome the disadvantages of poor cold toughness and low hot strength of MoSi 2 ceramic materials,Mo[Si 0.9 (Al 0.04 Mg 0.06 )] 2 ceramics were prepared by hot pressing sintering through the synergistic toughening of MoSi 2 by Mg and Al alloying.The MoSi 2 composite ceramics were post-treated by annealing.The effects of the annealing temperature (1 300,1 400,1 500 and 1 600 ℃),annealing duration (3,6,9 and 12 h) on the phase composition,microstructure,density and mechanical properties were studied.The results show that the annealing temperature has great influence on the density and hardness of the Mo[Si 0.9 (Al 0.04 Mg 0.06 )] 2 ceramics;when the annealing temperature is 1 600 ℃,the density of the ceramic specimen reaches 98.23%,and the hardness and fracture toughness values are the highest;the annealing duration also has some influence on the structure and properties of Mo[Si 0.9 (Al 0.04 Mg 0.06 )] 2 ceramics:with the extension of the annealing duration,the density,hardness and fracture toughness increase to different degrees;when the annealing duration is 12 h the density reaches 98.71%;when the annealing duration is 9 h ,the mechanical properties are the best.