Surface Phase Transitions in Alloys

9530469温布拉特这项研究包括两个主要推动力。第一个重点是铅合金表面粗化-刻面和预熔相变的模拟。它扩展了之前一项拨款的研究，在那项拨款中，蒙特卡洛和分子动力学计算技术得到了开发。着重介绍了铅-铋-镍合金的表面成分和粗化-刻面相变。第二个推力是对镓-铅系统中液态合金的润湿转变的实验方法。用扫描俄歇微探针技术研究了超高真空环境下液态金属体系的润湿转变。这使得可以对表面成分进行监测，以确保表面没有随机污染物。多元合金系统的研究引入了组成作为变量，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体系的%表面容易出现偏析现象。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，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. ***