Plastic deformation of MoSi2 single crystals
- 1 October 1995
- journal article
- research article
- Published by Taylor & Francis in Philosophical Magazine A
- Vol. 72 (4) , 1075-1097
- https://doi.org/10.1080/01418619508239954
Abstract
The deformation behaviour of MoSi2 single crystals has been studied as a function of crystal orientation in the temperature range from - 196 to 1500°C in compression. While [001]-oriented crystals can be plastically deformed only at high temperatures above 1300°C, plastic flow is possible from temperatures as low as room temperature for single crystals with orientations other than [001]. Five slip systems { 110)(111], {011)(100], {010)(100], {023)(100] and {013)(331] are identified to be operative, depending on crystal orientation. An anomalous increase in critical resolved shear stress (CRSS) is observed in the intermediate-temperature range for the former three slip systems. The anomalous temperature range as well as the magnitude of such an anomaly varies with slip system. The Schmid law is generally valid for the {110)(111], {011)(100] and (023)(100] slip systems. In particular, this is the case even in the temperature range of the anomaly in CRSS for the {110)(111j system. In contrast, the CRSS for {013)(331] strongly depends on crystal orientation with the higher values for orientations closer to [001]. This makes the [001] orientation the hardest orientation. On the basis of the results obtained, deformation mechanisms of MoSi2 single crystals including the anomalous increase in CRSS with temperature are discussed. Implications for improvements in the mechanical properties of polycrystalline MoSi2 at ambient temperatures are also briefly discussed.Keywords
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