【作者】 沈融融；

【导师】 祖方遒；

【作者基本信息】 合肥工业大学 ， 材料加工工程， 2006， 硕士

【摘要】 液态结构和性质的认识与许多领域的科学技术进步息息相关。温度诱导的非连续液-液结构转变现象打破了液体结构及性质随温度的升高而连续变化的传统观念。然而,这一现象的普适性（范围、条件及规律）及本质仍尚不明了。 本文主要利用电阻法对三种合金系统（In-Sn、Sn-Sb、Pb-Zn）发生温度诱导非连续液-液结构转变的可能性及其规律与特征进行了深入的探索: 首先,通过对三种合金系熔体的实验研究发现,并不是所有合金中都会出现不连续的液-液结构转变现象。其中,由于半金属Sb对合金熔体结构的影响,只有部分成分的Sn-Sb合金具有这种转变现象,电阻率的突变被认为是高温时富Sn端合金中金属键的断裂所引起的,而在对几种成分的Pb-Zn合金的研究中,则完全没有发现这种现象。 其次,为了探索二元合金在升温过程中所出现的液—液结构转变现象在降温过程中是否具有可逆性,我们对具有结构转变的In-Sn、Sn-Sb合金的降温过程进行了电阻率研究。其中,In-Sn合金升温过程中出现的温度诱导的不连续的结构转变的可逆性与合金成分紧密相关的,In_（1-x）Sn_x（x=49.1,70）两种成分合金的固态相区属于共晶形成的两相区,共晶组织中特殊的原子之间的相互作用使其熔体性质具有特殊性,出现了可逆的结构转变现象。而Sn-Sb合金中冷却后的组织相分布均匀,不足以引起熔体能量和熵的不连续变化,因此所出现的转变现象则完全不具有可逆性。 总体来看,“温度诱导不连续液-液结构转变”在不同合金及成分中存在现象与规律的多样性。其是否发生及可逆性,以及结构转变的温度范围,随合金系统的不同和成分的改变而不同。本文对这些规律均进行了总结,并就相关现象及规律进行了讨论和理论分析。 本文的研究结果及所观察到的现象不仅有助于进一步地认识液态物质结构与性质,同时也为研发新型合金材料、开拓及改进材料加工工艺方法提供了科学依据。更多还原

【Abstract】 Liquid-liquid structural change has become a common concern in liquid physics these years, which enriches the phenomenology in liquid physics and shed light on the structure and property of liquid materials. However, the essence of this phenomenon is still seldom known.The measurement of electrical resistivity has already been successfully applied in investigating the electrical properties and testifying anomalous change in some binary alloys. In this paper, we carry on investigation of the temperature dependence of electrical resistivity (p-T) and structure analysis of liquid In-Sn、 Sn-Sb and Pb-Zn alloy.First, we introduce the electricity behavior of In-Sn alloy in cooling process based on the former investigation of liquid structure in heating process. The reversibility of the structure change is mainly investigated in this chapter. Study mainly focuses on the reversibility of such temperature-induced liquid-liquid discontinuous transition.Second, chapter four mainly gives the investigation of p-T in Sn-Sb alloys. Temperature-induced structure change is believed to occur in some compositions of liquid Sn-Sb alloys, which may due to the remaining covalent and heterogeneous bonds and different bonding ability between Sn and Sb atoms.Also, the electricity of liquid Pb-Zn alloy is measured. This alloy is characterized by its low gasifacating temperature. Results show that no discontinuous structure transition occurs in Pb-Zn alloy with low percentage zinc.更多还原