论文部分内容阅读
从液态快冷得到的非晶态合金,它的内部结构保持了类似液态结构的特征,在热力学上处于非平衡态。若在低于玻璃化温度下进行等温退火,它内部的几何短程序和化学短程序会向能量较低的状态变化,同时伴随着一系列物理性能的变化。这就是结构弛豫现象。结构弛豫是一个复杂过程,直接观察相当困难,一般只能从一些物理性能的变化作间接的考察。用Cu_(80)Ti_(20)和Cu_(73)Ti_(12)(下标为重量百分比)的带状样品,从50℃开始,在保护气氛中,每隔50℃保温1小时做一次,直到400℃为止。用Mi44微型拉伸机对样品的力学性能进行测试;用πMT-3型硬度计测量显微硬度;利用浮力原理进行密度测量,并画出了力学性能和密度的变化曲线。结果表明:在50～200℃之间,随着温度增加,密度、断裂强度、显微硬度、塑性都减小,杨氏模量则是增加。在这个温度期间内,随温度升高,弛豫是向更混乱方向发展。对200～400℃之间的情况也作了讨论。
Amorphous alloys obtained from liquid quench, whose internal structure retains the characteristics of a liquid-like structure, are thermodynamically non-equilibrium. If isothermally annealed below the glass transition temperature, its internal short geometric and chemical short programs change to lower energies, accompanied by a series of changes in physical properties. This is the structural relaxation phenomenon. Structural relaxation is a complex process, the direct observation of quite difficult, generally only from some changes in physical properties for indirect investigation. The ribbon samples with Cu_ (80) Ti_ (20) and Cu_ (73) Ti_ (12) (wt%) were incubated at 50 ℃ for 1 hour in a protective atmosphere at 50 ℃ for 1 hour. Until 400 ℃ so far. The mechanical properties of the samples were tested with Mi44 micro-stretcher; the microhardness was measured with πMT-3 hardness tester; the density was measured by buoyancy principle; and the curves of mechanical properties and density were drawn. The results show that the density, the breaking strength, the microhardness and the ductility decrease with the increase of the temperature and the Young ’s modulus increase at the temperature between 50 and 200 ℃. During this temperature, relaxation is more chaotic with temperature. The case of between 200 and 400 ° C is also discussed.