(北京科技大學(xué) 材料科學(xué)與工程學(xué)院，北京 100083)
摘 要: 通過(guò)示差掃描量熱分析確定了Zr55Al10Ni5Cu30大塊非晶合金的過(guò)冷溫度區(qū)域范圍，采用應(yīng)變速率突變壓縮實(shí)驗(yàn)分析了合金在450 °C時(shí)的力學(xué)性能，研究了合金在不同擠壓速度、 不同真空度等工藝條件下的擠壓成形性能。 結(jié)果表明： Zr55Al10Ni5Cu30大塊非晶合金的玻璃化轉(zhuǎn)變開始溫度Tg為422.4 °C， 晶化開始溫度Tx為482.4 °C； 在450 °C、 應(yīng)變速率小于5×10-3 s-1的條件下，合金的流動(dòng)應(yīng)力小于40 MPa； 在擠壓速度為0.002～0.004 mm/s范圍內(nèi)擠壓時(shí)， 合金的最大擠壓載荷變化較小； 在擠壓溫度為450 °C時(shí)， 合金的最大擠壓力隨著真空度(2～2×10-3 Pa)的提高而增加； 大塊非晶合金在超塑性成形時(shí)呈現(xiàn)出比一般金屬材料更大的摩擦阻力。
關(guān)鍵字: 大塊非晶合金; 擠壓; 摩擦; 真空度
Zr55Al10Ni5Cu30 bulk metallic glass
（ School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China）
Abstract: Super-cooled liquid region was determined through differential scanning calorimetric, and mechanical properties were analysed by strain rate increase test for Zr55Al10Ni5Cu30 at 450 °C. The superplastic extrusion experiments were carried out under different extrusion velocities and vacuum degrees. The results show that the glass transition temperature Tg of Zr55Al10Ni5Cu30 is 422.4 °C, and the crystallization temperature Tx is 482.4 °C. At the temperature of 450 °C and strain rate less than 5×10-3 s-1, the flow stress of the alloy is less than 40 MPa. When extrusion velocities varying from 0.002 mm/s to 0.004 mm/s, the differences of maximal extrusion loads are not obvious. At 450 °C, the maximal extrusion load increases with the rising vacuum degrees (2-2×10-3 Pa). In superplastic forming, bulk metallic glass has larger surface friction resistance than ordinary metal alloys.
Key words: bulk metallic glass; extrusion; friction; vacuum degree
