A PROCESS MODEL FOR THE FRICTION WELDING OF AL-MG-SI ALLOYS AND AL-SIC METAL-MATRIX COMPOSITES .1. HAZ TEMPERATURE AND STRAIN-RATE DISTRIBUTION

The present investigation is concerned with the development of an overall process model for the microstructure and strength evolution during continuous drive friction welding of Al-Mg-Si alloys and Al-SiC metal matrix composites. In Part I the different components of the model are outlined and analytical solutions presented which provide quantitative information about the HAZ temperature distribution for a wide range of operational conditions. Moreover, a general procedure for modelling the HAZ strain mte distribution has been developed by introducing a series of kinematically admissible velocity equations which describe the material flow fields in the radial, the rotational, and the axial direction, respectively. Calculations performed for both types of materials show that the effective strain mte may exceed 1000 s-1 in positions close to the contact section due to the high rotational velocities involved. Application of the model for evaluation of the response of Al-Mg-Si alloys and Al-SiC metal matrix composites to the imposed heating and plastic deformation is described in an accompanying paper (Part II).