Modeling of precipitation hardening in Mg-based alloys
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This work deals with the development of Mg-based alloys with enhanced properties at elevated temperatures. This is achieved by precipitation of binary phases such as MgZn2 and Mg2Sn during the aging of these alloys. The aim of the present work is to develop and calibrate a model for precipitation hardening in Mg-based alloys, as different types of precipitates form simultaneously. The modified Langer-Schwartz approach, while taking into account nucleation, growth and coarsening of the new phase precipitations, was used for the analysis of precipitates’ evolution and precipitation hardening during aging of Mg-based alloys. Two strengthening mechanisms associated with particle-dislocation interaction (shearing and bypassing) were considered to be operating simultaneously due to particle size-distribution. Parameters of the model, RNi and kσ i, were found by fitting of calculated densities and average sizes of precipitates with ones estimated from experiments. The effective diffusion coefficients of phase formation processes, which determine the strengthening kinetics, were estimated from the hardness maximum positions on the aging curves.
KeywordsPrecipitation Hardening Effective Diffusion Coefficient Solid Solution Strengthen Equivalent Radius Transmission Electron Microscopy Investigation
The study was partially supported by the B. and N. Ginsburg Research Fund and German Israeli foundation for scientific research and development (GIF) under contract number I-704–43.10/2001. The foundations are acknowledged for their support.
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