Light metals and their alloys II : technology, microstructure and properties

259 Pages·2012·120.011 MB·English

by  Anna J Dolata, Maciej Dyzia

Light Metals
and their Alloys II

Technology,
Microstructure
and Properties
Edited by
Anna J. Dolata
Maciej Dyzia
Light Metals and their Alloys II

Technology, Microstructure
and Properties
Special topic volume with invited peer reviewed papers only.
Edited by
Anna J. Dolata and Maciej Dyzia
Copyright  2012 Trans Tech Publications Ltd, Switzerland

All rights reserved. No part of the contents of this publication may be reproduced or
transmitted in any form or by any means without the written permission of the
publisher.

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Volumes 191 of
Solid State Phenomena
ISSN 1662-9787
(Pt. B of Diffusion and Defect Data - Solid State Data (ISSN 0377-6883))
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Introduction

Faculty of Materials Engineering and Metallurgy was established in 1966 and currently is one
of the 13 Faculties of Silesian University of Technology, located in Katowice. At present the
faculty structure includes four departments: Metallurgy, Materials Technology, Materials
Science and Management and Computer Science. The Faculty employs 38 professors and
associate professors as well as 120 doctors (PhD). Scope of research activities includes
materials engineering and metallurgy. The works carried out at the faculty are focused on
research and development of advanced materials and their potential applications. Many
scientific investigations are connected with problems of new technologies, formation the
structure and properties of lightweight materials.
This is the next collection of 30 articles presenting the results of research in scope of light
metal alloys. That issue include three chapters: I – aluminium alloys, II – magnesium alloys
and III – titanium alloys.
Chapter I presents the subjects relating to the manufacturing of aluminum alloys, grain
refinement and welding joints. This chapter presents also result of investigations concerning
methods of obtaining and properties of aluminium matrix composites.
Chapter II contain the papers presenting the results of researches carried out on conventional
and new casting magnesium alloys. The first group of articles concern the effects of
modification on the structure and properties of casting alloys. Following papers present results
of researches on plastic deformation of Mg alloys. Subsequent articles cover topics related to
the welding technologies. Last part of the chapter concern the magnesium matrix composites.
Results of researches carried out on new generation of titanium alloys are presented in
Chapter III. Papers included in this section concern the microstructure and properties Ti-Al
base alloys. As well, possibilities of heat treatment and diffusion brazing of Ti alloys are
discussed.

This project is the second in the series of volume in the range of light metal alloys. The
authors are planning to continue the series and publish every year.

Editors.
Table of Contents
Introduction
Chapter 1: Aluminium and Aluminium Alloys
Numerical and Physical Modelling of Aluminium Refining Process Conducted in URO-200
Reactor
M. Saternus and T. Merder 3
Hydrodynamics of the Aluminium Barbotage Process Conducted in a Continuous Reactor
M. Saternus 13
Influence of Overheating Degree on Material Reliability of A390.0 Alloy
J. Piątkowski 23
Mechamism of Grain Refinement in Al after COT Deformation
K. Rodak and J. Pawlicki 29
Deformation-Induced Grain Refinement in AlMg5 Alloy
K. Rodak, J. Pawlicki and M. Tkocz 37
CMT and MIG-Pulse Robotized Welding of Thin-Walled Elements Made of 6xxx and 2xxx
Series Aluminium Alloys
J. Adamiec, T. Pfeifer and J. Rykała 45
Fabrication of Ceramic-Metal Composites with Percolation of Phases Using GPI
A. Boczkowska, P. Chabera, A.J. Dolata, M. Dyzia, R. Kozera and A. Oziębło 57
Producing of Composite Materials with Aluminium Alloy Matrix Containing Solid
Lubricants
A. Posmyk and J. Myalski 67
Machinability of Aluminium Matrix Composites
J. Wieczorek, M. Dyzia and A.J. Dolata 75
Influence of Particles Type and Shape on the Corrosion Resistance of Aluminium Hybrid
Composites
A.J. Dolata, M. Dyzia and W. Walke 81
Course of Solidification Process of AlMMC – Comparison of Computer Simulations and
Experimental Casting
R. Zagórski, A.J. Dolata and M. Dyzia 89
Chapter 2: Magnesium and Magnesium Alloys
Plasticity and Microstructure of Hot Deformed Magnesium Alloy AZ61
D. Kuc, E. Hadasik and I. Bednarczyk 101
Effect of Modification on the Structure and Properties of QE22 and RZ5 Magnesium Alloys
S. Roskosz, B. Dybowski and J. Paśko 109
Influence of Mould Cooling Rate on the Microstructure of AZ91 Magnesium Alloy Castings
S. Roskosz, B. Dybowski and R. Jarosz 115
Fractography and Structural Analysis of WE43 and Elektron 21 Magnesium Alloys with
Unmodified and Modified Grain Size
S. Roskosz, B. Dybowski and J. Cwajna 123
Precipitate Processes in Mg-5Al Magnesium Alloy
A. Kiełbus 131
Influence of Pouring Temperature on Castability and Microstructure of QE22 and RZ5
Magnesium Casting Alloys
B. Dybowski, R. Jarosz, A. Kiełbus and J. Cwajna 137
The Influence of Section Thickness on Microstructure of Elektron 21 and QE22 Magnesium
Alloys
M. Stopyra, R. Jarosz and A. Kiełbus 145
b Light Metals and their Alloys II
The Influence of Tin on the Microstructure and Creep Properties of Mg-5Al-3Ca-0.7Sr-
0.2Mn Magnesium Alloy
T. Rzychoń and B. Chmiela 151
On the Oxidation Behaviour of WE43 and MSR-B Magnesium Alloys in CO Atmosphere
2
R. Przeliorz and J. Piątkowski 159
Galvanic Corrosion Test of Magnesium Alloys after Plastic Forming
J. Przondziono, W. Walke and E. Hadasik 169
Creep Resistance of WE43 Magnesium Alloy Joints
A. Kierzek and J. Adamiec 177
Impact of Heat Treatment on the Structure and Properties of the QE22 Alloy Welded Joints
A. Kierzek and J. Adamiec 183
Microstructure of In Situ Mg Metal Matrix Composites Based on Silica Nanoparticles
A. Olszówka-Myalska, S.A. McDonald, P.J. Withers, H. Myalska and G. Moskal 189
Microstructure of Mg-Ti-Al Composite Hot Pressed at Different Temperature
A. Olszówka-Myalska, R. Przeliorz, T. Rzychoń and M. Misiowiec 199
Chapter 3: Titanium and Titanium Alloys
The Chemical Composition and Microstructure of Ti-47Al-2W-0.5Si Alloy Melted in
Ceramic Crucibles
W. Szkliniarz and A. Szkliniarz 211
Grain Refinement of Ti-48Al-2Cr-2Nb Alloy by Heat Treatment Method
A. Szkliniarz 221
Characteristics of Corrosion Resistance of Ti-C Alloys
A. Szkliniarz and R. Michalik 235
Effect of a High-Temperature Hydrogen Treatment on a Microstructure and Surface
Fracture in Titanium Ti-6Al-4V Alloy
M. Sozańska 243
Diffusion Brazing of Titanium via Copper Layer
M. Różański and J. Adamiec 249
CHAPTER 1:

Aluminium and Aluminium Alloys
© (2012) Trans Tech Publications, Switzerland
doi:10.4028/www.scientific.net/SSP.191.3
Numerical and physical modelling of aluminium refining process
conducted in URO-200 reactor
Mariola Saternus1, a, Tomasz Merder1, b
1Silesian University of Technology, ul. Krasińskiego 8, 40-019 Katowice, Poland
a [email protected], b [email protected]
Keywords: aluminium refining, physical modelling, numerical modelling.
Abstract. At present both primary and secondary aluminium needs to be refined before further
treatment. This can be done by barbotage process, so blowing small bubbles of inert gas into liquid
metal. This way harmful impurities especially hydrogen can be removed. Barbotage is very
complex taking into consideration hydrodynamics of this process. Therefore modelling research is
carried out to get to know the phenomena that take place during the process better. Two different
modelling research can be applied: physical and numerical. Physical modelling gives possibility to
determine the level of gas dispersion in the liquid metal. Whereas, numerical modelling shows the
velocity field distribution, turbulent intensity and volume fraction of gas.
The paper presents results of physical and numerical modelling of the refining process taking place
in the bath reactor URO-200. Physical modelling was carried out for three different flow rate of
refining gas: 5, 10 and 15 dm3/min and three different rotary impeller speeds: 0, 300, 500 rpm
Commercial program in Computational Fluid Dynamics was used for numerical calculation. Model
VOF (Volume of Fluid) was applied for modelling the multiphase flow.
Obtained results were compared in order to verify the numerical settings and correctness of the
choice.
Introduction
Today, both primary and secondary aluminium contains many impurities such as hydrogen or
nonmetallic and metallic inclusions. Hydrogen content in aluminium and its alloys is in the range
between 0.05 to 0.6 cm3/100g Al [1]. To reduce hydrogen concentration to the level 0.06 – 0.07
cm3/100g Al refining process is applied. Additionally, parts of nonmetallic and metallic inclusions
can be simultaneously eliminated by means of flotation. Therefore, aluminium refining process has
become one of the integral technological stages in obtaining aluminium. The most commonly used
method is barbotage that means blowing the inert gases, especially argon into the liquid aluminium.
There are different kinds of refining reactors: batch and continuous. Small gas bubbles are
generated by ceramic porous plugs, different kind of nozzles and rotary impellers. All over the
world there are many technological solutions of such reactors, for example: ACD, AFD, Alcoa 622,
ASV, DMC, DUFI, JetCleaner, GBF, GIFS, Hycast, LARS, MINT, RDU, Rotoxal, Shizunami
[2,3]. In Poland one of the most popular reactors is the URO-200 reactor designed by IMN-OML in
Skawina. This reactor works in many polish foundries. The problem connected with this type of
reactor is obtaining the uniform dispersion of gas bubbles in the whole volume of liquid. The
influence on this has the following processing parameters: flow rate of refining gas and mainly the
rotary impeller speed. The choice of these parameters allows to optimize the industrial aluminium
refining process.
Main information about modelling
Generally, the barbotage process is characterized by high dynamics of course because of the quick
mass transfer between phases. So, it is essential to understand the phenomena occurring during the
process and determine the hydrodynamic conditions in which the process takes place. They
influence directly the value of mass exchange area and the mass transfer coefficient. Obtaining the
4 Light Metals and their Alloys II
appropriate size of gas bubbles and their dispersion in the liquid metal ensures good efficiency of
the process. The process of gas bubbles creation and their movement is very complex, so its
analytical description present fundamental difficulties. As a solution in this case, modellling
research is applied. In metallurgy there are many methods of modelling the liquid flow (see Fig. 1).

Fig. 1. Modelling of the liquid flows applied in metallurgy [4]

The hydrodynamic conditions can be determined by the physical modelling. However, the flow of
mass and gas is not fully shown by this modelling, these kinds of research are very often and
willingly [5-9] used due to difficulties in conducting experimental test in real conditions (sometimes
this is even impossible). Additionally, modelling research is not as expensive as the one carried out
in industrial conditions. This method gives possibility to obtain information about phenomena
occurring in the liquid metal during the blowing process of gas bubbles. Water is used as a
modelling agent of aluminium. It is applied because its accessibility, low costs, and especially the
fact that some physical features of water in room temperature are similar to features of aluminium
in temperature 700 0C (e.g. dynamic viscosity).
If the results obtained from this kind of research are to be representative and can be transferred into
the real conditions, the physical model has to be built according to the strict rules coming from the
theory of similarity [10-13]. This similarity concerns the characteristic features of the real object
that have important influence on the phenomena occurring in the examined process. Taking into
account the construction of the examined metallurgical units it is essential to fulfill the following
conditions:
(cid:1) geometric similarity of the model and a real object,
(cid:1) hydrodynamic similarity for the liquid flow in the model and the object which especially
concerns: kinetic similarity, dynamic similarity, heat similarity.
Fulfillment of the similarity rules according to the theory of dimensional analysis, can be done
basing on the equality rule of the appropriate criterial numbers in the model and the examined
object. The results obtained from the experimental test on the physical model, after verification, can
be transferred to the real conditions. Taking into account both - the construction of refining reactors
used for the barbotage process and the hydrodynamics of the metal flow, the adequate criterial