Solidification kinetics of a Cu-Zr alloy: ground-based and microgravity experiments

D M Herlach,R Hanke,E V Kharanzhevski,J Gegner,W Dreier,S Koch,P K Galenko,M Rettenmayr,P Paul

doi:10.1088/1757-899x/192/1/012028

Abstract

Experimental and theoretical results obtained in the MULTIPHAS-project (ESA-European Space Agency and DLR-German Aerospace Center) are critically discussed regarding solidification kinetics of congruently melting and glass forming Cu50Zr50 alloy samples. The samples are investigated during solidification using a containerless technique in the Electromagnetic Levitation Facility [1]. Applying elaborated methodologies for ground-based and microgravity experimental investigations [2], the kinetics of primary dendritic solidification is quantitatively evaluated. Electromagnetic Levitator in microgravity (parabolic flights and on board of the International Space Station) and Electrostatic Levitator on Ground are employed. The solidification kinetics is determined using a high-speed camera and applying two evaluation methods: “Frame by Frame” (FFM) and “First Frame – Last Frame” (FLM). In the theoretical interpretation of the solidification experiments, special attention is given to the behavior of the cluster structure in Cu50Zr50 samples with the increase of undercooling. Experimental results on solidification kinetics are interpreted using a theoretical model of diffusion controlled dendrite growth.

Highlights

A valuable progress in the investigation of glass forming metals and alloys has been made since their discovery by Turnbull [3]
Data sets for dendrite growth velocities in CuZr samples have been obtained under microgravity conditions in parabolic flights (Airbus A310 Zero-G)
Kobold [6] obtained a second growth regime which is confirmed by our present measurements

Summary

Introduction

A valuable progress in the investigation of glass forming metals and alloys has been made since their discovery by Turnbull [3]. A favourable advantage of the containerless methods is the prevention of heterogeneous nucleation, which in turn allows for a better investigation of the effects of high undercoolings and rapid growth conditions on the solidification of metals and alloys. The present work is devoted to a systematic view on recent results obtained regarding solidification of the congruently melting and glass forming Cu50Zr50 alloy.

Methods

Results

Discussion

Conclusion