Characterisation of Solidified Microstructure of Solid Solutions / Charakterisierung des Erstarrungengefüges in Mischkristallen

Abstract

First this paper gives a summary of the solidified structures of solid solutions, the solidification methods, and the investigation possibilities of solidified structures. Afterwards through an example the influences of the solid/liquid interface velocity on the dendrite morphology in the case of steady-state unidirectional solidification are shown. Al-4 wt% Cu alloy was used as testing material. The temperature gradient at the solid/liquid interface was 1500 K/m and the moving velocities of samples were 5 x 10 -5 , 2 x 10 -4 and 8 × 10 -4 m/s. The purpose of experiments was the accurate numerical determination of the typical parameters of the dendritic structure. The amount of the second phase (Al 2 Cu), as well as the primary, the secondary and the tertiary dendrite arm spacing were measured. For quantitative characterisation the image analyser equipment type Quantimet 500 Image Workstation was used. The measured values were studied as a function of the solid/liquid interface velocities.