Study on effect of strain rate on 3D surface asperity flattening in uniaxial planar compression by crystal plasticity finite element modelling
As an important parameter of surface quality for metal manufacturing products, surface roughness is affected by the following parameters: original roughness, friction, grain size, grain orientation, stress- strain state, and work hardening. Previously, effects of friction and gauged reduction and wavelength on surface roughness have already been studied by a 2D surface asperity model in uniaxial planar compression. On the basis of previous results, a 3D surface asperity model is developed by employing rate-dependent crystal plasticity constitutive model in finite element software ABAQUS. Results from electron back scatter diffraction(EBSD) and atomic force microscope(AFM) experiments have also been input into the 3D model. Influences of strain rate and texture have been discussed in this paper. The calculated results show a good agreement with experimental results. With an increase of reduction, the surface asperity flattening under a lower strain rate tends to accelerate; grain size and roughness decrease while hardness and stress increase. Under the same reduction, surface roughness with higher strain rate 0.01 s1 has a larger flattening rate (lower roughness Ra) than that of surface roughness with lower strain rate 0.001 s1. In this study, increased strain rate has no obvious effect on texture.