Dynamic fracture of metals in wide range of strain rates
A model of dynamic tensile fracture is constructed,which is applicable for many metals in wide range of strain rate.It considers a stage of thermofluctuation nucleation of voids and stages of voids growth and aggregation.The model contains two fitted parameter for each substance: the first parameter is a specific free energy of metal surface; the second one is a distribution parameter for weakened zones of material.These parameters are found for copper,aluminum,iron,titanium,nickel and molybdenum by fitting with the experimental data and molecular-dynamics simulations.Calculations show that there are two regions with different slope in the strain rate dependence of strength: in the first one (at strain rate <108 s-1) voids are nucleated in weakened zones,and strength grows up relatively fast with strain rate; in the second one (at strain rate>108 s-1) number of weakened zones becomes insufficient,voids are nucleated predominantly in perfect material,and the strength growth is decelerated.Plasticity is not effect on voids nucleation and on the material strength at the strain rate >107 s–1,but it becomes a dominant factor at the strain rate<104 s-1.
Fracture High-rate tension Metal Micro-cracks Two-level approach
Alexander E.Mayer
Department of Physics,Chelyabinsk State University,Chelyabinsk,454001,Russia
国际会议
北京
英文
1-9
2013-06-16（万方平台首次上网日期，不代表论文的发表时间）