Plastic deformation of single crystals of NbSi2 with the C40 structure

[摘要] The deformation behavior of single crystals of NbSi2 with the C40 structure has been investigated as a function of crystal orientation in the temperature range from room temperature to 1500 degrees C in compression. Plastic flow is possible only when slip along (<1(2)over bar 10>) on (0001) is operative and no other slip systems are observed in the whole temperature range investigated. While plastic flow is observed above 500 degrees C for as-grown crystals, the onset temperature for plastic flow is lowered by 300 degrees C when the crystal is prestrained at 1400 degrees C and then re-deformed at low temperatures, The critical resolved shear stress (CRSS) for basal slip decreases with increasing temperature but exhibits a moderate peak around 1300 degrees C, In the temperature range where the anomaly in the CRSS is observed, the stress-strain curve is usually accompanied by serration. The deformation mechanism of NbSi2 is discussed in comparison with that reported for isostructural CrSi2. (C) 1997 Elsevier Science S.A.

[发布日期] 1997-12-01

[效力级别]  Proceedings Paper

[关键词] NbSi2;transition-metal silicide;C40 structure;dislocation;Portevin Le Chatelier effect;high-resolution transmission electron microscopy