(中南大学 粉末冶金国家重点实验室， 长沙 410083)
摘 要: 以喷雾干燥-H↓2还原法制备的纳米级90W-7Ni-3Fe复合粉末为原料， 采用模压成型并在800℃保温120min的条件下对试样进行预烧， 研究了试样在不同烧结温度和不同烧结时间下的烧结特性，采用高倍SEM和光学金相分别对断口进行了形貌观察和钨晶粒测试；对烧结样的相对密度、 抗拉强度、 延伸率等性能进行了测定与分析。 结果表明： 保温时间为120min时， 随着烧结温度的提高， 试样的性能有显著的变化， 当烧结温度为1390℃时， 试样的抗拉强度和延伸率都达到一个极大值，分别为900MPa和13%， 此时试样的相对密度为99.0%； 当烧结温度为1390℃时， 随着烧结时间的延长， 试样的性能也有显著的变化， 试样的抗拉强度、延伸率和相对密度都达到一个极大值； 平均钨晶粒度为15~20μm， 钨晶粒呈球形或近球形； 复合粉末烧结活性高， 比传统烧结温度降低80~120℃； 试样中出现了W30.73Ni40.21Fe29.06过渡相。
关键字: 90W-7Ni-3Fe合金；纳米粉末； 复合粉末； 烧结特性
（ State Key Laboratory of Powder Metallurgy,
Central South University, Changsha 410083, China）
Abstract: Nanometer 90W-7Ni-3Fe composite powder synthesized by spray drying-H2 reduction method was pressed and pre-sintered at 800℃ for 120min. Sintering characteristic of samples were studied at different sintering temperatures and durations. Fracture morphology and W crystalline sizes were measured by SEM and optical morphology, respectively. Relative density, tensile strength and elongation of samples were also measured and analyzed. The results show that when sintering time is 120min, properties of samples change evidently with increasing sintering temperature. Relative density, tensile strength and elongation of samples arrive at maximum values of 99.0%, 900MPa, 13% at 1390℃, respectively. When sintering temperature is 1390℃, properties of samples change evidently with increasing sintering time. Relative density, tensile strength and elongation of samples arrive at maximum, too. Average W crystalline sizes are 15-20μm and W crystalline morphology are spherical or nearly spherical. Sintering temperature is lower 80-120℃ than general sintering because of higher sinterability of composite powder. Middle phase W30.73Ni40.21Fe29.06 appears in matrix phase.
Key words: 90W-7Ni-3Fe alloy； nanometer powder； composite powder； sintering properties
