© Copyright by International OCSCO World Press. All rights reserved. 2008
VOLUME 28
ISSUE 2
June
2008
Research paper 131
of Achievements in Materials
and Manufacturing Engineering
of Achievements in Materials
and Manufacturing Engineering
Thermal and structural characteristics
of the AM50 magnesium alloy
W. Kasprzak
a, c,
*, J.H. Sokolowski
b
, M. Sahoo
a
, L.A. Dobrzański
c
a
CANMET Materials Technology Laboratory, 568 Booth Street, Ottawa,
Ontario, K1A 0G1, Canada
b
Light Metals Casting Technology Group, University of Windsor,
401 Sunset Avenue, Windsor, Ontario, Canada, N9B 3P4
c
Division of Materials Processing Technology, Management and Computer Techniques
in Materials Science, Institute of Engineering Materials and Biomaterials,
Silesian University of Technology, ul. Konarskiego 18a, 44-100 Gliwice, Poland
* Corresponding author: E-mail address: wojciech.kasprzak@nrcan.gc.ca
Received 26.03.2008; published in revised form 01.06.2008
Materials
AbstrAct
Purpose: The goal of this publication is to demonstrate the laboratory metal casting simulation methodology
based on controlled melting and solidification experiments. The thermal characteristics of the AM50
magnesium alloy during melting and solidification cycles were determined and correlated with the test samples’
microstructural parameters.
Design/methodology/approach: A novel methodology allowed to perform variable solidification rates for
stationary test samples. The experiments were performed using computer controlled induction heating and
cooling sources using Argon for melt protection and test sample cooling.
Findings: Thermal analysis data indicated that the alloy’s melting range was between approximately 434 and
640°C. Increasing the cooling rate from 1 to 4°C/s during solidification process reduced the Secondary Dendrite
Arm Spacing from approximately 64 to 43μm. The temperatures of the metallurgical reactions were shifted
toward the higher values for faster solidification rates. Fraction liquid curve indicates that at the end of melting
of the α(Mg)-β(Mg17Al12) eutectic, i.e., 454.2ºC the alloy had a 2% liquid phase.
Research limitations/implications: Future research is intended to address the development of a physical
simulation methodology representing very high solidification rates used by High Pressure Die Casting (HPDC)
and to assess the microstructure refinement as a function of solidification rates.
Practical implications: Advanced simulation capabilities including non-equilibrium thermal and structural
characteristics of the magnesium alloys are required for the development of advanced metal casting technologies
like vacuum assisted HPDC and its heat treatment.
Originality/value: The presented results point out the direction for future research needed to simulate the alloy
solidification in a laboratory environment representing industrial casting processes.
Keywords: Casting; AM50 alloy; Thermal analysis; Solidification
1. Introduction
Interest in magnesium alloy technologies for automotive
applications has grown over the last 60 years since its first
application for the VW beetle in 1946. Recent requirements for
reduction of vehicle weight has triggered a stronger interest in
magnesium applications due to tighter emission requirements.
Unfortunately, unstable magnesium prices and a lack of large
scale applications in the past resulted in limited research and
1. Introduction