Study of the Nanometric Grain Size Distribution in Iron Compacts Obtained by Mechanical Milling

Abstract

Abstract.A study has been carried out on the grain size distribution of cylindrical compacts obtained by consolidation of iron powder severely deformed by mechanical milling. Consolidation has been performed in two consecutive steps: cold and hot conditions. The hot one was done at two temperatures, namely 425 and 475ºC. After milling, the iron powder has a grain size of 8 nm (± 4 nm) with an average hardness of 800 HV. After hot compaction the grain size increases up to 50 nm, especially at 475ºC where a small fraction of grains reach larger values than the average. The grain size was evaluated by two different techniques, X-Ray Diffraction and Transmission Electron Microscopy. Results showed some differences between both methods. The advantage of using TEM is that grain size distribution, and not only the average size, can be obtained. Small discs were also obtained from the compacted specimen in order to fracture them on a "ball on three balls" equipment. The fracture behaviour of the samples was then studied by SEM.

Structure and Electrical Properties of AlFe Matrix Composites with Graphene

“…From this point of view, Al-Fe alloys are a good base for new and promising conductive alloys due to the low solubility of iron in an Al solid solution. Various techniques are used for strengthening such materials: rapid solidification [13], thermal treatment [14], mechanical alloying [15,16], and severe plastic deformation (SPD) [17][18][19][20]. Such a vast choice of treatments allows one to vary the composition, morphology, and size of iron-containing intermetallic phases, which determine the mechanical and electrical properties of the alloy as a whole.…”