Plasticity Mechanism of Indium Antimony (InSb) in the Brittle Regime: Combined Study with Conventional TEM and LACBED
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1026-C11-01
Plasticity Mechanism of Indium Antimony (InSb) in the Brittle Regime: Combined Study with Conventional TEM and LACBED Bouzid Kedjar, Ludovic Thilly, Jean-Luc Demenet, and Jacques Rabier Laboratoire de Métallurgie Physique-SP2MI, University of Poitiers, SP2MI, Teleport 2, BP30179, Bd Curie, Futuroscope, 86962, France ABSTRACT Indium antimony (InSb) has been deformed in compression under gaseous confining pressure (Paterson apparatus) above and below the brittle to ductile transition occurring around 150°C. Thin foils have been prepared from the deformed samples and dislocations were characterized with conventional TEM as well as LACBED. This paper focuses on the room temperature deformation microstructures which appeared to be extremely complex with the observation of very well arranged network of perfect and partial dislocations. In such case, the traditional dislocation extinction conditions were extremely difficult to apply and only the use of the LACBED technique uncovered the nature of the observed dislocations and gave further insight to their interactions, revealing in particular the presence of partial dislocation dipoles. These original observations suggest a change of deformation mechanism at the brittle to ductile transition temperature. INTRODUCTION Elemental and compound Semi-Conductors (SCs) exhibit drastically different mechanical behavior with respect to temperature: at elevated temperature, they are ductile and deform by nucleation and glide of lattice dislocations while below about 0.5Tm (where Tm is the melting temperature) they are brittle and exhibit no plasticity before massive failure by crack propagation [1]. Since the dislocations are usually detrimental to the electronic properties of SCs and the origin of the Brittle to Ductile Transition (BDT) is still not clear, the study of plasticity of SCs is still of great interest for technical applications and fundamental reasons. The deformation microstructure above the BDT Temperature, TBDT, is usually well known because of the relative simplicity to deform SCs in the ductile regime. However at low temperature and below TBDT, i.e. in the brittle regime, specific deformation techniques must be used to prevent early failure of the specimen such as pre-deformation at high temperature to introduce dislocations in the lattice or compression under solid confinement (Griggs apparatus, multi-anvils) [1, 2]. More recently, compression tests under gaseous confinement (Paterson apparatus) have been performed to study the BDT in quasicrystals and SiC [3, 4]: the same technique has been used here to study the deformation mechanisms of III-V compound SC indium antimony (InSb) above and below TBDT. InSb has been chosen for its low TBDT, around 150°C, and deformed in the temperature range [20°C-400°C] under gaseous confining pressure. Thin foils have been prepared from the deformed samples and dislocations were characterized with conventional TEM (diffraction contrast technique in Bright Field, BF, Dark Field, DF and Weak Beam, WB) and Large Angle Co
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