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Processing Temperature Effects on Molybdenum Disilicide
Author(s) -
Wade Robert K.,
Petrovic John J.
Publication year - 1992
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1992.tb04406.x
Subject(s) - transgranular fracture , materials science , fracture toughness , indentation , eutectic system , grain size , metallurgy , vickers hardness test , molybdenum , fracture (geology) , composite material , microstructure , grain boundary , intergranular fracture
A series of MoSi 2 compacts were fabricated at increasing hot‐pressing temperatures to achieve different grain sizes. The materials were evaluated by Vickers indentation fracture to determine room‐temperature fracture toughness, hardness, and fracture mode. From 1500° to 1800°C, MoSi 2 had a constant 67% transgranular fracture and linearly increasing grain size from 14 to 21 μm. Above 1800°C, the fracture percentage increased rapidly to 97% transgranular at 1920°C (32‐μm grain size). Fracture toughness and hardness decreased slightly with increasing temperature. MoSi 2 processed at 1600°C had the highest fracture toughness and hardness values of 3.6 MPa.m 1/2 and 9.9 GPa, respectively. The effects of SiO 2 formation from oxygen impurities in the MoSi 2 starting powders and MoSi 2 –Mo 5 Si 3 eutectic liquid formation were studied.