摘要
利用材料测试系统(MTS)、X-Ray 衍射(XRD)和扫描电镜(SEM)等手段研究了Nd 基大块金属玻璃的变形行为和断裂特征。Nd 基大块金属玻璃样品在室温下是脆性断裂,大约在500 K 时变形模式从非均匀变形转变为均匀变形,在523 K 以上表现出显著的塑性变形。在5×10-4 m/s 的应变速率下,这种Nd 基大块金属玻璃材料在523 K^600 K 之间出现明显的屈服应力下降现象,随后进入1 种稳定的粘性流动状态,而且这种屈服下降现象与温度和应变速率有关。这种在过冷液相区的变形行为与其他大块金属玻璃变形特征相似。合金的这种塑性变形行为表明了其存在稳定的过冷液相区,同时对其变形行为的研究有助于进一步了解Nd 基大块金属玻璃的反常热稳定性。
The deformation behaviors and the fracture properties of the Nd-based bulk metallic glasses (BMG) were studied by X-ray diffraction (XRD), material testing system(MTS) and scanning electronic microscope(SEM). The alloy is extremely brittle at room temperature and no plastic deformation. The deformation mode changes from inhomogeneous deformation to homogeneous deformation around 500 K. At a high strain rate of 5 x 10(-4) m(.)s(-1), a stress overshoot followed by a viscous flow approaching a steady state can be seen in the stress-strain curves within the temperature range from 523 K to 623 K. Moreover, the flow behavior of the BMG is strongly dependent on the strain rate and temperature. This mechanical behavior is similar to that of other BMGs deformed near supercooled liquid region. The results indicate that the glass transition and supercooled liquid region exist in the Nd-based bulk metallic glasses which is beneficial to the further understand of the anomalous thermal stability in this system.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2005年第3期371-374,共4页
Rare Metal Materials and Engineering
基金
国家自然科学基金(50101012)
湖南省杰出青年基金(02JJyB010)
关键词
大块金属玻璃
力学性能
玻璃转变
bulk metallic glass
mechanical properties
glass transition
