Consolidation and mechanical behaviour of nanocrystalline iron powder

Abstract

Iron nanopowders, with an average diameter of 5100 nm, were consolidated using plasma pressure compaction (P 2 C). The consolidated samples produced were of the order of 15 mm in diameter and 4 . 1 mm thick. The time and pressure of compaction were varied in order to study the effects of processing variables on the microstructure and the mechanical behaviour in compression of the materials. It was found that the compliance of the loading curves was a function of the mesoscale porosity in the specimens. The strain to failure was found to be a function of the porosity on the microscale. The optimal strength and ductility were achieved in specimens in which a fully dense (on the microscale), platelet structure had developed.MST/5257

One-step synthesis of air-stable nanocrystalline iron particles by thermal decomposition of triiron dodecacarbonyl

“…The synthesis of magnetic nanoparticles is of interest to researchers in both academia and industry due to their wide range of applications in magnetic and electronic devices [1][2][3], medicine [4] and new technologies such as environmental remediation [5]. The magnetic behavior of these systems has been found to be particularly dependent on their crystalline character and on their size and size distribution.…”

Microstructure and Tensile Properties of Nanostructured and Ultrafine Grained FeMoB Alloys Produced by Spark Plasma Sintering of Mechanically Alloyed Powders

“…Density of the borides is 7.30 g/cm 3 (Fe 2 B) and 8.44 g/cm 3 (FeMo 2 B 2 ) whilst for (Fe,Mo) 23 B 6 it is not available; it is 7.38 g/cm 3 for Fe 23 B 6 and is expected to increase due to the presence of substitutional Mo. Assuming the same Fe/Mo ratio of the base powder, density of the metastable boride is 7.43 g/cm 3 . Theoretical density of the various sintered materials was then calculated using data from Fig.…”

“…The structural refining in the submicrometric range causes a large increase in hardness and yield strength and a decrease of the ductile-to-brittle transition temperature of metallic materials, combined with a decrease of tensile ductility due to the occurrence of plastic instability phenomena (Ref [1][2][3][4]. Among the various methods used to produce nanostructured metals (Ref 5), sintering of high energy milled powders may represent a valid alternative provided that sintering is accomplished by minimal grain growth.…”

52nd Hatfield Memorial LectureLarge chunks of very strong steel

“…The recent search has been for processes which reduce the grain size dramatically to ,1 mm. [38][39][40] Fine grains represent one of the few mechanisms available to increase both strength and toughness. What then is the theoretical minimum grain size that can be achieved using this technology?…”