Mechanically alloyed nanocrystalline iron and copper mixture: behavior andconstitutive modeling over a wide range of strain rates

A comprehensive study on the response of a nanocrystalline iron and copper mixture (80% Fe and 20% Cu) to quasi-static and dynamic loading is performe d, The constitutive model developed earlier by Khan, Huang & Liang (KHL) is extended to include the responses of nanocrystalline metallic materials. T he strain rate and grain size dependent behaviors of porous nanocrystalline iron-copper mixture were determined experimentally for both static and dyn amic loading. A viscoplastic model is formulated by associating the modifie d KHL model (representing the fully dense matrix behavior), and Gurson's pl astic potential which provides the yield criteria for porous material. Simu lations of uniaxial compressive deformations of iron-copper mixture with di fferent initial porosity, grain size and at a wide range of strain rate (10 (-4) to 10(3) s(-1)) are made. The numerical results correlate well with th e experimental observations. (C) 2000 Elsevier Science Ltd. All rights rese rved.