Ab initiostudy of the ideal tensile strength and mechanical stability of transition-metal disilicides

Abstract

The ideal tensile test in transition metal disilicides MoSi 2 and WSi 2 with a C11 b structure is simulated by ab initio electronic structure calculations using the full-potential linearized augmented plane wave method. The theoretical tensile strength for [001] loading is determined for both disilicides and compared with that of other materials. A full relaxation of all external and one internal structural parameter is performed, and the influence of each relaxation process on energetics and strength of materials studied is investigated. Differences in the behavior of various interatomic bonds including tension-compression asymmetry are analyzed and their origin in connection with the changes of the internal structural parameter is traced. For comparison, the response of bonds in MoSi and CoSi with B2 structure to the [001] loading is also studied. The ideal tensile test in transition metal disilicides MoSi 2 and WSi 2 with a C11 b structure is simulated by ab initio electronic structure calculations using the full-potential linearized augmented plane wave method. The theoretical tensile strength for ͓001͔ loading is determined for both disilicides and compared with that of other materials. A full relaxation of all external and one internal structural parameter is performed, and the influence of each relaxation process on energetics and strength of materials studied is investigated. Differences in the behavior of various interatomic bonds including tension-compression asymmetry are analyzed and their origin in connection with the changes of the internal structural parameter is traced. For comparison, the response of bonds in MoSi and CoSi with B2 structure to the ͓001͔ loading is also studied.

Ab initio study of the anomalous volume-composition dependence in Fe–Al alloys

“…the choice of the exchange-correlation potential (here the GGA) that is known to underestimate the equilibrium lattice constant of iron (see e.g. [29]), and (ii) a conceptual difference between zero-temperature defect-free static crystals assumed in the calculations and finitetemperature measurements. Nevertheless, the main features of the anomaly are well reproduced.…”

The role of ab initio electronic structure calculations in studies of the strength of materials

“…These studies included calculation of the tensile strength for [0 0 1] loading and analysis of bonds and their changes during the test [64][65][66]. Theoretical tensile strength of iron in the loading direction [0 0 1] was determined in [67][68][69][70][71][72]; in [69,70], we compared the results obtained in [67,68] and calculated the tensile strength of iron for uniaxial loading in the [1 1 1] direction.…”

Size-dependent structural phase transition of face-centered-cubic metal nanowires

“…The critical stresses can be read directly on stress-strain curves, which are fitted from the energy-strain curves according to the following equation 46 :…”