Enhanced Densification of PM Steels by Liquid Phase Sintering with Boron-Containing Master Alloy
Artikel i vetenskaplig tidskrift, 2018

Reaching high density in PM steels is important for high-performance applications. In this study, liquid phase sintering of PM steels by adding gas-atomized Ni-Mn-B master alloy was investigated for enhancing the density levels of Fe- and Mo- prealloyed steel powder compacts. The results indicated that liquid formation occurs in two stages, beginning with the master alloy melting (LP-1) below and eutectic phase formation (LP-2) above 1373 K (1100 °C). Mo and C addition revealed a significant influence on the LP-2 temperatures and hence on the final densification behavior and mechanical properties. Microstructural embrittlement occurs with the formation of continuous boride networks along the grain boundaries, and its severity increases with carbon addition, especially for 2.5 wt pct of master alloy content. Sintering behavior, along with liquid generation, microstructural characteristics, and mechanical testing revealed that the reduced master alloy content from 2.5 to 1.5 wt pct (reaching overall boron content from 0.2 to 0.12 wt pct) was necessary for obtaining good ductility with better mechanical properties. Sintering with Ni-Mn-B master alloy enables the sintering activation by liquid phase formation in two stages to attain high density in PM steels suitable for high-performance applications.

master alloy

densification

PM steels

boron

Liquid phase sintering

Författare

Maheswaran Vattur Sundaram

Yt- och mikrostrukturteknik

Kumar Babu Surreddi

Eduard Hryha

Yt- och mikrostrukturteknik

Angela Veiga

Sigurd Berg

Fransisco Castro

Lars Nyborg

Yt- och mikrostrukturteknik

Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science

1073-5623 (ISSN)

Vol. 49 255-263

Drivkrafter

Hållbar utveckling

Styrkeområden

Produktion

Materialvetenskap

Ämneskategorier

Bearbetnings-, yt- och fogningsteknik

Metallurgi och metalliska material

DOI

10.1007/s11661-017-4383-4