COST 507 - Repositório Aberto da Universidade do Porto

Thermophysical Properties of Light Metal Alloys
D9
G.Jaroma-Weiland 1 , R.Brandt 1 , P.Relpert 2 , G.Neuer 1
'Forschungsinstitut für Kerntechnik und Energiewandlung e.V., Stuttgart, Germany
2 Kolbenschmidt AG, Neckarsulm, Germany
Abstract
In the factual data base THERSYST experimental data on therrnophysical properties of Al-,
Mg- and Ti-based alloys have been stored. Thermal conductivity and hardness of six
industrial Al-Si-based alloys have been intensively investigated as a function of temperature
and time. From these measurements the phenomenological correlation between thermal
conductivity and hardness has been found. Electrical resistivity were determined on 11
ternary Al-Si-Zn alloys. For specimens with Zn-content greater than 20wt% a phase
transition was observed around 290°C.
1 Introduction
Due to the low density of the light metal alloys they are gradually becoming more and more
attractive. For optimum application the short and long term material properties of the alloys,
such as strain and stress relation, fatigue strength, wear and corrosion resistance, etc. must
be known. Data on thermophysical properties (thermal conductivity, thermal diffusivity,
electrical resistivity, specific heat capacity and thermal expansion) of these alloys are of
interest in two aspects:
Many components are exposed to temperatures up to 400°C, resulting in generation
of stationary and transient temperature fields. The knowledge of the temperature
dependence of the thermal conductivity enables the calculation of the temperature
distributions.
Data for higher temperatures Including the so called "mushy" zone and the melting
range are necessary for numerical solidification models used in the casting industry.
Therefore it was one of the aims of the European research programme COST507 to study
transport properties of light metal alloys to provide reliable experimental data and to
characterize each alloy family. The experimental data on thermophysical properties
available in the literature have been stored in the factual data base THERSYST
[89Neu/Bra].
Experimental investigations have been performed at selected industrial Al-Si-based casts.
Thermal conductivity and hardness have been measured as function of temperature and
time. We attempted to find a correlation between these properties in order to reduce the
expenses of thermal conductivity measurements in future.
Electrical resistivity was measured on ternary Al-Si-Zn alloys. The thermodynamic
evaluation of this system has been performed during 1st round of COST507-action
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