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The Temperature and Strain Rate Dependence of the Flow Stress in MoSi2 Single Crystals

Published online by Cambridge University Press:  25 February 2011

S.A. Maloy
Affiliation:
Center for Materials Science, MS-K765, Los Alamos National Laboratory, Los Alamos, NM 87545
T.E. Mitchell
Affiliation:
Center for Materials Science, MS-K765, Los Alamos National Laboratory, Los Alamos, NM 87545
John J. Petrovic
Affiliation:
MST-4, MS-G771, Los Alamos National Laboratory, Los Alamos, NM 87545
A.H. Heuer
Affiliation:
Department of Materials Science and Engineering, Case Western Reserve University, Cleveland, OH 44106
J.J. Lewandowski
Affiliation:
Department of Materials Science and Engineering, Case Western Reserve University, Cleveland, OH 44106
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Abstract

The temperature dependence of the flow stress and deformation mechanisms of single crystal MoSi2 have been determined for compression along three different orientations, [001], [021] and [771], at two different strain rates, 1 × 10−5/s and 1 × 10−4/s, and at temperatures between 900 and 1600°C. The flow stress along [021] is slightly higher than that along [771] while both orientations gave a much lower flow stress than that along [001]. Along [021], slip occurs on the {110} 1/2<111> slip system between 1000 and 1200°C, while at 1300-1400°C, slip occurs on the {013}<100> slip system. Along [771], deformation occurs by the [001]<100> slip system while cross-slip onto {013} and [011] planes is observed at 1000-1300°C except that slip occurs on the {013{1/2<331> slip system at 1000-1100°C for faster strain rates. Along [001], slip occurs on the {013}1/2<331> system at 900-1100°C while slip is observed on the {011} 1/2<111> system at 1300-1600°C. Strain rate jump tests from 1×10−5/s to 5x10−5/s at 1 100°C revealed a stress exponent of 7 along [771] and 20 along [021], while a rate jump test from lx10−5/s to 2x 10−5/s along [001] at 1400°C gave a stress exponent of 3.9.

Type
Research Article
Copyright
Copyright © Materials Research Society 1994

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