CuAlNi合金的液态结构(英文)

Microstructure of Liquid CuAlNi Shape Memory Alloy

利用高温X射线衍射研究了CuAlNi合金液态结构,发现结构因子上有明显的预峰出现,随着温度的升高,Cu75Al25合金熔体结构因子的预峰减弱,直到1300℃预峰消失,这表明中程有序原子团簇可以在高于液相线温度约250℃范围内存在,原子团簇的大小和数量都随着Ni的加入而增加,Ni增强原子之间的交互作用,有利于中程有序的形成,根据预峰的特性,提出CuAlNi合金液态结构的原子模型,即由八面体结构共享顶点形成的原子团簇与无规密堆积原子分布区域组成.

Molten CuAlNi alloys have been investigated by X-ray diffractometer. Distinct pre-peaks have been found in the structure factors. For the liquid alloy Cu75Al25, the intensity of pre-peak decreases with increasing temperature but exists clearly up to temperature of 1 300 ℃. This behaviour indicates the existence of medium-range order clusters up to nearly 250 ℃ above liquidus temperature. The amount and size of atomic clusters increase as the concentration of Ni increases. The addition of Ni can improve the interaction between atoms, so it is favorable to the ability of medium-range order formation. According to the characteristics of the pre-peak, the atomic model of liquid CuAINi is constructed, namely, the structure of liquid CuAINi is a combination of clusters consisting of octahedrons with shared vertexes and other atoms with random dense atom distribution.