The Effect of Segregation on Grain Boundary Fracture in Poly-Crystalline Alloys: Beneficial Versus Harmful Segregants

控制塑性或脆化的机制 铁锰、铂铑钨、铱和镍 铝化物的存在少量的杂质将是 研究了 这些合金代表了一系列的晶体结构 并将允许一个测试的一般性观察 方面的影响. 对掺杂有以下物质之一的材料进行的Hall-Petch实验 将进行延性化或脆化杂质测定， 杂质对晶界 阻止滑移的传递。 相对测量 杂质在表面和晶界上的偏聚行为 将被制造。 TEM中的原位变形将提供详细的 了解滑移传动的机理。

The mechanisms that control the ductility or embrittlement in iron-manganese, platinum-rhodium-tungsten, iridium, and nickel aluminide by the presence of small amounts of impurities will be studied. These alloys represent a range of crystal structures and will allow one to test the generality of the observed effects. Hall-Petch experiments on materials doped with either ductilizing or embrittling impurities will be done to determine the effect of impurity on the ability of grain boundaries to impede the transmission of slip. Measurement of the relative impurity segregation behavior to surfaces and grain boundaries will be made. In situ deformation in TEM will provide a detailed understanding of the mechanisms involved in slip transmission.