The influence of BN additives on the phase composition, microstructure and mechanical properties of 316L steel consolidated by spark plasma sintering

P Jenei,Á Horváth,J Gubicza,Cs Balázsi,K Balázsi

doi:10.1088/1757-899x/426/1/012020

Abstract

Blends of commercial 316L steel and boron nitride (BN) were consolidated using Spark Plasma Sintering (SPS). The components were mixed by high energy milling (using attritor) before sintering. The aim was to study the effect of BN on the microstructure and the mechanical properties. Two composites containing 0.5 and 2 wt.% BN were produced beside a pure 316L specimen. It was found that bimodal grain size distribution formed during the production. A bcc α’-phase formed during milling beside the main fcc γ-phase. The addition of BN resulted in a slightly higher dislocation density and a smaller grain size in the fine grained parts of the samples. At the same time, the elastic modulus and the strength determined by bending test were reduced, most probably due to the weak bonding between the 316L and the BN grains, and the lower fraction of α’-phase.

Highlights

Ceramic dispersion strengthened steels are promising structural materials in new generation nuclear reactors and future fusion power plants [1,2,3,4]
The components of the matrix and the disperse phase are blended by mechanical milling, which is usually followed by a high-temperature consolidation process
3a shows a part of the X-ray diffraction pattern obtained for the 316L+0.5BN sample

Summary

Introduction

Ceramic dispersion strengthened steels are promising structural materials in new generation nuclear reactors and future fusion power plants [1,2,3,4]. The addition of BN resulted in a slightly higher dislocation density and a smaller grain size in the fine grained parts of the samples. The effect of the phase composition, the porosity, the grain size and the dislocation density on the mechanical properties will be discussed.

Results

Conclusion