4M Knowledge base - papers

J-F. Charmeux (a), R. Minev (a), S. Dimov (a), E. Minev (a)
(a)Manufacturing Engineering Center, Cardiff University, Cardiff, CF24 3AA, UK

Abstract

Producing micro-castings trough vacuum investment casting is known to be associated with high cooling rates due to small scale of the castings. High cooling rates together with alloy composition might be the main factors affecting the final metallographic structure of castings’ alloys during the solidification process. When using Al-Si-Mg casting alloys, the size of the dendritic structure can be used for a non-destructive test to assess the mechanical properties and overall quality of the castings. Also the ability of the alloys to be structured by different mechanical and energy assisted processes is highly dependant on their metallographic structure. Based on earlier experimental results, this paper proposes an empirical model describing the degree of dendrite cell refinement in cast microfeatures as a function of their AR and mould pouring temperature. Additionally, the paper reports the strong correlation between the DCS refinement and the changes in the mechanical properties of the castings through MHV measurements following a Hall-Petch equation type.