Microstructural analysis and high-temperature strength of a directionally solidified Er[sub 2]Mo[sub 3]Si[sub 4]-MoSi[sub 2] eutectic

Journal Article · Fri Apr 15 00:00:00 EDT 1994 · Scripta Metallurgica et Materialia; (United States)

DOI:https://doi.org/10.1016/0956-716X(94)90541-X· OSTI ID:5226139

Patrick, D K ^[1]; Van Aken, D C ^[2]

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1. Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Materials Science and Engineering
2. Univ. of Missouri, Rolla, MO (United States). Dept. of Metallurgical Engineering

Recent investigations have shown that Er[sub 2]Mo[sub 3]Si[sub 4] is an effective reinforcement for strengthening MoSi[sub 2]. When present in hot-pressed MoSi[sub 2] compacts, the Er[sub 2]Mo[sub 3]Si[sub 4] improved both hot hardness and creep resistance of the MoSi[sub 2]. The crystal structure of Er[sub 2]Mo[sub 3]Si[sub 4], as reported by Bodak et al., is monoclinic with lattice parameters of 0.667 nm, 0.689 nm, and 0.681 nm. The point group and space group of this phase have been identified as 2/m and P2[sub 1]/c, respectively. A theoretical density for Er[sub 2]Mo[sub 3]Si[sub 4] was calculated to be 8.25 g/cm[sup 3] and this compares favorably with other refractory silicide compounds (e.g., Mo[sub 5]Si[sub 3] = 8.25 g/cm[sup 3]). Because of the low crystal symmetry, this intermetallic compound is expected to exhibit limited plasticity, but may possess good high temperature mechanical properties. Mechanical property data on Er[sub 2]Mo[sub 3]Si[sub 4] is still quite limited; however, preliminary creep results from a decremental step-strain rate test show that the directionally solidified (DS) Er[sub 2]Mo[sub 3]Si[sub 4]-MoSi[sub 2] eutectic has excellent creep resistance at 1,300 C. At this temperature a flow stress of 625 MPa was observed for a strain rate of 5 [times] 10[sup [minus]5]s[sup [minus]1], but failure occurred as the strain rate was reduced to 10[sup [minus]5]s[sup [minus]1]. In this paper the authors present further results obtained from constant engineering strain rate compression tests on the same DS eutectic bar.

• OSTI ID: 5226139
• Journal Information: Scripta Metallurgica et Materialia; (United States), Vol. 30:8; ISSN 0956-716X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COMPOSITE MATERIALS
MECHANICAL PROPERTIES
MICROSTRUCTURE
ERBIUM SILICIDES
MOLYBDENUM SILICIDES
EXPERIMENTAL DATA
REINFORCED MATERIALS
DATA
ERBIUM COMPOUNDS
INFORMATION
MATERIALS
MOLYBDENUM COMPOUNDS
NUMERICAL DATA
RARE EARTH COMPOUNDS
REFRACTORY METAL COMPOUNDS
SILICIDES
SILICON COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
360602* - Other Materials- Structure & Phase Studies
360603 - Materials- Properties