(中南大學(xué) 粉末冶金國家重點實驗室， 長沙 410083)
摘 要: 以噴霧干燥-H↓2還原法制備的納米級90W-7Ni-3Fe復(fù)合粉末為原料， 采用模壓成型并在800℃保溫120min的條件下對試樣進(jìn)行預(yù)燒， 研究了試樣在不同燒結(jié)溫度和不同燒結(jié)時間下的燒結(jié)特性，采用高倍SEM和光學(xué)金相分別對斷口進(jìn)行了形貌觀察和鎢晶粒測試；對燒結(jié)樣的相對密度、 抗拉強(qiáng)度、 延伸率等性能進(jìn)行了測定與分析。 結(jié)果表明： 保溫時間為120min時， 隨著燒結(jié)溫度的提高， 試樣的性能有顯著的變化， 當(dāng)燒結(jié)溫度為1390℃時， 試樣的抗拉強(qiáng)度和延伸率都達(dá)到一個極大值，分別為900MPa和13%， 此時試樣的相對密度為99.0%； 當(dāng)燒結(jié)溫度為1390℃時， 隨著燒結(jié)時間的延長， 試樣的性能也有顯著的變化， 試樣的抗拉強(qiáng)度、延伸率和相對密度都達(dá)到一個極大值； 平均鎢晶粒度為15~20μm， 鎢晶粒呈球形或近球形； 復(fù)合粉末燒結(jié)活性高， 比傳統(tǒng)燒結(jié)溫度降低80~120℃； 試樣中出現(xiàn)了W30.73Ni40.21Fe29.06過渡相。
關(guān)鍵字: 90W-7Ni-3Fe合金；納米粉末； 復(fù)合粉末； 燒結(jié)特性
XIONG Xiang, WANG Deng-long
（ 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
