Trends in the strength and hardness of tantalum at high temperatures

Effect of temperature on mechanical characteristics of copper–chromium composite

“…In the region of premelting temperatures (above (0?75-0?8)T melt ), owing to a high diffusive atomic mobility, the deformation occurs with the vacancy concentration close to equilibrium one and, therefore, with the activation energy equal to the activation energy of selfdiffusion. 13,18 From Fig. 2 one can see that the temperature dependences of the tensile strength, proof strength, and hardness of Cu-Cr composite in the range under study consist of four portions within which they are linear and satisfy equations ( 1) and ( 2).…”

“…Despite the fact that those models often contradict one another, they allow more or less satisfactory description of the temperature dependences of the mechanical properties of metallic materials obtained empirically. 13,14 Thermodynamic activation analysis of the composite was used to estimate its strength and hardness variations with temperature by a procedure presented earlier. 13,15 To establish basic regularities in the strength variation over the temperature range under study, the following exponential equations describing the temperature dependences of strength and hardness were used…”

“…13,14 Thermodynamic activation analysis of the composite was used to estimate its strength and hardness variations with temperature by a procedure presented earlier. 13,15 To establish basic regularities in the strength variation over the temperature range under study, the following exponential equations describing the temperature dependences of strength and hardness were used…”

“…Moreover, unlike some other empirical models, it has a serious physical justification. 13 In Fig. 2 the experimental data obtained are presented in the ln R p0?2 , ln R m , ln HV-1/T coordinates.…”

“…For fcc metals of IB group of the periodic table, which are used as electrocontact materials (Cu, Ag, Au), inflections of the curves of the temperature dependences of mechanical characteristics are observed at y0?35, 0?5 and 0?65T melt . 13,15 In this respect, the plots of the strength and hardness temperature dependences are diagrams of the Ashby deformation mechanisms. 16,17 According to Ashby, for fcc metals of group IB under the investigated conditions, the mechanisms of dislocation sliding are acting at temperatures below 0?5T melt and the mechanisms of dislocation creep at higher temperatures.…”