Papers by Keyword: Mutual Diffusion

Abstract: Recently, the demand for long life to industrial products has risen. The high strength alloy coating on necessary part can decrease a manufacturing cost for life prolongation. This study proposes a laser surface alloying method to form an Fe-Al alloy coating on a carbon steel. By laser heating to an Al foil stuck on the steel, the mutual diffusion proceeds and the Fe-Al alloy grows. The material property of the generated alloy is greatly different according to a heat treatment temperature. For example, Fe₃Al grows at 950 °C or more, and it has high toughness. A furnace heating effects the properties of inside of base material negatively. A high-frequency heating is not suitable for a local surface reforming. The laser processing is suitable for a local surface reforming. A defocused CO₂ laser was irradiated to the Al foil stuck on the steel block by the shot lining in various processing conditions. The metal structures of the laser irradiated area was observed, to search for the suitable processing conditions for alloy coating. It was clarified that a local Fe-Al alloy coat was able to be formed without change of the properties of base material by high speed laser scanning.

Abstract: A nanostructured powder with uniform distribution of Ni and Cu powders was produced by means of the Ball Mechanical Alloying Treatment (BMAT). Mutual diffusion of Ni and Cu in the nanostructured layer and the microstructure of the cross section of the remaining powders were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Electron Probe Microanalyzer (EPMA). X-ray diffraction patterns revealed that increasing the milling time gives rise to decreasing crystallite size and lattice parameter during the MA process. Furthermore, scanning electron microscopy (SEM) was utilized not only for evaluating the morphology and microstructure of the remaining powder particles but also for proving this claim that during MA process, the mutual diffusion of Ni and Cu has occurred. Elemental mappings also show that the alloying process occurred in samples but obtaining the uniform shape, size and microstructure of the powder requires increase in the milling time.