中文摘要：

分别通过还原气氛常压烧结法（TFS）和放电等离子烧结法（svs）制各Mo5SiB2（T2）相合金，并采用XRD，SEM和TEM等方法对合金的微观结构进行表征．结果表明：快的升温速率是合成T2相的动力学条件，相比传统烧结方式，SPS法以独特的等离子活化烧结方式提供快的加热速率，能够在较短的时间内升温到所需温度1500℃，避免Mo，Si和B混合粉末在中温区间（600-1200℃）通过固一固反应生成Mo3Si，Mo5Si3和MoB等二元相，而通过固-液反应原位合成T2相．合金平均晶粒尺寸为1．44μm，晶界清晰、洁净、无过渡区且在晶体内没有观察到位错等缺陷。

英文摘要：

Mo5SiB2 （T2） can be used as a promising elevated-temperature structural material because of its high melting temperature （about 2200 ℃ ）, and excellent resistance to oxidation and creep. The Mo5SiB2 （T2） alloy was prepared by both spark plasma sintering （SPS） and tube furnace sintering （TFS）, and then the microstructures were characterized by XRD, SEM-EDS and TEM. The results show that the rapid heating rate is one of important dynamic conditions responsible for the synthesis of T2. Compared with traditional methods, SPS can provide the fast synthesis in a particular way of labilized plasma sintering so that the sample can be heated to the expected tem- perature of 1500 ℃ with a short period. The melted Si can rapidly react with Mo and B to synthesize T2 in the sol- id-liquid state prior to the formation of binary phases （Mo3Si, Mo5Si3, MoB, etc.） in the solid state in the range of 600-1200 ℃. The average size of grains is equal to 1.44 μm. The boundaries are clear and have the shape of a straight line without transition zones. Moreover, no defects such as dislocations were found in the T2 alloys prepared by SPS.