Surface Phase Transitions in Alloys

9530469温布拉特 这项研究包括两个主要方面。 第一部分着重于铅合金表面粗糙化-刻面和预熔相变的模拟。 它扩展了以前资助的研究，其中开发了Monte Carlo和分子动力学计算技术。 强调了铅铋镍合金的表面组成和粗糙化-小面化相变。 第二个推力是一个实验方法，在液态合金中的镓铅系统的润湿转变。 利用扫描俄歇微探针技术研究了真空环境下液态金属体系的润湿转变。 这允许监测表面成分，以确保表面不含随机污染物。 多元合金体系的研究引入了成分变量，从而扩展了过去强调纯固体的研究。 含有一种以上成分的合金系统的表面易发生偏析现象。 表面偏析与许多材料问题有关，包括腐蚀、氧化、磨损和材料加工， 等 如烧结和连接。 ***

9530469 Wynblatt This research consists of two main thrusts. The first focuses on the modeling of surface roughening -faceting and premelting phase transitions in lead alloys. It extends research from a previous grant in which Monte Carlo and Molecular Dynamics computational techniques were developed . Surface compositional and roughening-faceting phase transitions in lead-bismuth-nickel alloys are emphasized. The second thrust is an experimental approach to wetting transitions in liquid alloys in the gallium-lead system. A scanning Auger microprobe technique is used to study wetting transitions in liquid metallic systems under an ultrahigh vacuum environment. This permits surface composition monitoring for assurance that surfaces are free of random contaminants. The study on multicomponent alloy systems introduces composition as a variable thereby extending past research which emphasized pure solids. %%% Surfaces of alloy systems containing more than one component are subject to segregation phenomena. Surface segregation is relevant to many materials problems, including corrosion, oxidation, wear, and materials processing , such as sintering and joining. ***