Influence of composition, grain size, and oxide particles on the strength of consolidated ball-milled iron

6th International Conference on Nanomaterials by Severe Plastic Deformation

材料科学;化学

Benito, J.A.^1,2 ; Gregoire, V.^3,4 ; Casas, C.^2,3 ; Cabrera, J.M.^2,3

EUETIB, Universitat Politècnica de Catalunya, C/Comte d'Urgell 187, Barcelona 08036, Spain^1

Fundació CTM Centre Tecnològic, Plaça de la ciencia 2, 08243 Manresa, Spain^2

ETSEIB, Universitat Politècnica de Catalunya, Av. Diagonal 647, Barcelona 08028, Spain^3

Eeigm, Université de Lorraine, 6 rue Bastien-Lepage CS 10630, F-54010 Nancy, France^4

关键词: Abnormal grain growth;    Bimodal grain-size distribution;    Grain boundary strengthening;    Increasing temperatures;    Low oxygen contents;    Lower temperatures;    Particle strengthening;    Strength and ductilities;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/63/1/012024/pdf
DOI  :  10.1088/1757-899X/63/1/012024

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

In this paper iron powders with two oxygen content (0.2 and 0.6% wt.) have been mechanically milled and consolidated by hot static pressing at different temperatures to obtain different grain sizes. At lower temperatures the grain size was in the nanostructured and ultrafine range and with increasing temperature abnormal grain growth was observed for both compositions. This led to the development of bimodal grain size distributions. In the samples with lower oxygen content the grain size and the percentage of coarse grain areas were larger than in the case of high oxygen content. The strength and ductility have been determined by tensile tests. For low oxygen content, the presence of large coarse grains allowed plastic strain in some cases, and for the samples consolidated at higher temperatures, yield strength of 865 MPa with a 8% total strain were obtained. For the samples with high oxygen content plastic deformation was no possible in any case. The observed stress for both compositions was analysed by two approaches, one based exclusively in grain boundary strengthening and the other one based in two effects acting at the same time: grain boundary and particle strengthening. Whereas grain boundary strengthening seems to fit with the strength of the samples in the nanostructured range, when coarse ferrite grains appear the addition of particle strengthening help to get better results. This indicates that the presence of oxides dissolved inside the large grains reinforce the structure of ball-milled iron.