TY  - JOUR
U1  - Zeitschriftenartikel, wissenschaftlich - begutachtet (reviewed)
A1  - Modigell, Michael
A1  - Koke, Johannes
T1  - Time-Dependent Rheological Properties of Semi-Solid Metal Alloys
JF  - Mechanics of Time-Dependent Materials
N2  - Semi-solid metal alloys, as used in thixoforming, have a special microstructure of globular grains suspended in a liquid metal matrix. The complex rheological properties are strongly influenced by the local solid fraction, particle shape, particle size and state of agglomeration. There is a high demand for models and software tools allowing the simulation of semi-solid casting processes. The material under investigation is a tin-lead alloy (Sn-15%Pb) which exhibits a similar microstructure to aluminium alloys. The experiments were performed with a concentric cylinder rheometer of the Searle type. Initially, the liquid alloy is cooled down to the semi-solid range under constant shearing and then kept under isothermal conditions for further experimentation. Based on the experimental data, a single-phase model has been derived where the semi-solid alloy is regarded as a homogeneous material with thixotropic properties and the microstructure is characterised by a structural parameter. The model consists of two parts: the equation of state, including a finite yield stress, and a rate equation for the structural parameter. The model equations are employed in numerical software and used for the simulation of characteristic filling cases and the comparison with the conventional filling.
KW  - semi-solid materials
KW  - modelling
KW  - simulation
KW  - suspensions
KW  - thixoforming
KW  - thixotropy
Y1  - 1999
U6  - https://doi.org/10.1023/A:1009856708511
DO  - https://doi.org/10.1023/A:1009856708511
VL  - 3
IS  - 1
SP  - 15
EP  - 30
ER  -