Table Of ContentShahrooz Nafisi · Reza Ghomashchi
Semi-Solid
Processing of
Aluminum
Alloys
Semi-Solid Processing of Aluminum Alloys
Shahrooz Nafisi • Reza Ghomashchi
Semi-Solid Processing
of Aluminum Alloys
ShahroozNafisi RezaGhomashchi
UniversityofAlberta TheUniversityofAdelaide
Edmonton,AB,Canada Adelaide,SA,Australia
ISBN978-3-319-40333-5 ISBN978-3-319-40335-9 (eBook)
DOI10.1007/978-3-319-40335-9
LibraryofCongressControlNumber:2016944927
©SpringerInternationalPublishingSwitzerland2016
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Foreword
Withthepublicationofthisbook,itisjust45yearssincetheseminaldoctoralthesis
of David B. Spencer laid the foundation for semi-solid metal (SSM) processing.
Research interest remains high in developing the fundamentals of semi-solid
forming,andindustrialapplicationsofthesefundamentalscontinuetogrow.
Theauthorsofthisbookhavehadalonganddistinguishedcareerinthefieldof
solidification processing and have collaborated very closely since 2003 on the
solidification and metallurgy of aluminum alloys. This book is an outgrowth of
suchfruitfulcollaborationandaverydetailedstudyonthesemi-solidprocessingof
aluminumalloys.
Animportantstrengthofthebookisitsemphasisonfundamentals,includingon
howSSMmicrostructureevolvesandhowstirringandthermalvariablescan alter
the structure andalloy distribution.The fundamentals ofsolidificationareused to
interpretnucleation,growth,anddisintegrationofprimaryphaseparticles.Impor-
tant points are made regarding characterization of SSM structures including the
roadmap,“methodology,”andnecessarytoolsandequipmenttocharacterizesucha
structure.Thebookismainlyonrheocasting,butthixocastingalsoformsachapter.
SSMprocessesavailableorintheprocessofbeingdevelopedaredescribed.
IndustrialapplicationsareoutlinedinachapterbyDr.SteveMidson,basedon
hisdecadesofexperienceinthefield,mostrecentlyinChina,whereSSMresearch
anddevelopmentiscurrentlyparticularlystrong.Thetimealsoappearsripeforan
expansionofSSMactivitiesinotherpartsofAsiaandintheWest.However,itmust
berecognizedthatmajorinnovations,suchasSSM,becomeadoptedonlyslowlyby
industries where capital costs are high, profit margins are modest, and failure to
meetcustomerrequirementscarryahighpenalty.
The still relative newness of industrial applications of the technology makes it
evidentthatincreasedindustrialutilizationoftheprocesswilldependoncontinuing
closecollaborationbetweenresearchersandproductionpersonnel.
Cambridge,MA MertonC.Flemings
June2016
v
Preface
Numerousmanufacturingtechniqueshavebeenimplementedfortheproductionof
nearnetshapecomponentsofmetalsandtheiralloys.Inprinciple,thesetechniques
could be categorized as liquid or solid based. Casting is a manufacturing route
initiatedfromliquid,whileforging,extrusion,androllingaresomeexamplesofthe
solid-based fabrication techniques. A new category of metallic alloys processing
wasintroducedduringthelastquarterofthetwentiethcenturycombiningthetwo
principles and inheriting both liquid and solid-based know-how. The new
processing route, the so-called semi-solid processing of alloys, claimed improved
quality at lower cost. The lower cost is mainly associated with tooling cost and
reduced energy consumption while achieving enhanced properties is due tobetter
control over microstructural evolution during the course of alloy processing and
partsfabrication.
Since the introduction of semi-solid metal (SSM) processing as a possible and
viablefabricationrouteintheearly1970satMIT,agreatdealofresearchhasbeen
carried out worldwide resulting in industrialization of the process. The process is
now gaining momentum as an effective alternative to the classical manufacturing
processesofcastingandforging.Knowledgeofdifferentroutesandunderstanding
theformationofslurries,includingtheapplicationofsolidificationscienceduring
SSM processing, are necessary for further development and also selection of the
optimum and most appropriate process, including process parameters, for any
application. This book provides a vast amount of knowledge and know-how for
SSM processes which is mandatory for any researcher, SSM technologist, and
educator. It is also useful for both undergraduate and graduate teaching of solidi-
fication and casting of metals and their alloys. This book demonstrates the meth-
odology and necessary tools and equipment to characterize semisolid metallic
alloys. It also provides the reader with the fundamental knowledge on semi-solid
metalprocesses.
After the introductory Chap. 1 on aluminum industry and its role in economic
development along with some useful statistics, Chap. 2 discusses the semi-solid
metal technologies available to date, while Chap. 3 concentrates on the
vii
viii Preface
solidification,stirring,andalloydistributionduringSSMprocessingofmainlyAl–
Si alloys. Chap. 4 gives a detailed account of the techniques used to characterize
SSM billets which include metallographic and flow behavior, i.e., rheological
characteristics. Chap. 5 is concentrated on rheocasting of Al–Si alloys where the
findings on SSM research are presented for rheocast billets produced by low
pouring temperature, electromagnetic stirring, EMS, and Swirled Enthalpy Equil-
ibration Device, SEED, processes. Chap. 6 explains the melt treatment currently
employedforSSMbillets,whileChap.7reportsontherecentfindingsofresearch
activities on the thixocast billets’ production routes. In Chap. 8, we have invited
Dr. Steve Midson, Midson group-Colorado School of Mines, to highlight some
industrial applications of SSM processes in the production of high-quality engi-
neeringparts.
The book is based on our research on SSM processes over the last 13 years
includingoneofourlatestpublicationswhichwasrecognized“2013winnerofthe
BuehlerTechnicalPaperMeritAwardforExcellence”byTheAwardsCommittee
ofthe International Metallographic Society andMetallography.As well,the book
covers the work of many researchers and other well-respected research centers
worldwide.Wearegratefultomanyofourcolleaguesandcollaboratorsaswellas
otherresearcherswhohavekindlyprovideduswiththeirresultsandpermissionto
include them in this book. We particularly wish to acknowledge the following
individualswhoseassistanceandcommentsmadethisworkpossibleandhelpedus
toovercomemanyhurdles:
• Dr.OmidLashkari,Canada
• Dr.AlirezaHekmat,Canada
• Prof.EugenioJoseZoqui,UniversityofCampinas,Brazil
• Dr. Frank Czerwinski, CanmetMATERIALS, Natural Resources Canada/Gov-
ernmentofCanada
• Prof.JessadaWannasin,PrinceofSongklaUniversity,Thailand
• Dr.PeymanAshtari,Canada
• Prof.MagnusWesse´n,J€onk€opingUniversity,Sweden
• Dr.JayeshPatel,ZyomaxLtd,UK
• Dr.JimYurko,USA
• Drs.ShanJin,andHai-LinChen,ThermoCalc,Sweden
• PascalCote´,STASInc.,Canada
• DjibrilRene´,EuropeanAluminiumAssociation,Belgium
• Ve´roniqueBouchard,Trans-AlNetwork,Canada
• MattMeenan,TheAluminumAssociation,USA
• RosannaBoyd,AustralianAluminiumCouncil,Australia
An enormous task of finalizing the book was about acquiring permission for
materialsweusedinthiscontextandwewouldliketoacknowledgetheassistance
ofthefollowing:
• Prof.PlatoKapranos,SheffieldUniversity,UK
• Prof.DavidSt.John,QueenslandUniversity,Australia
Preface ix
• Prof.HaoWang,UniversityofSouthernQueensland,Australia
• Prof.MertonFlemings,MIT,USA
• JohnJorstad,USA
• Prof.AnnalisaPola,Universit(cid:2)adegliStudidiBrescia,Italy
• StephenLeBeau,Thixomat,Inc.,USA
• Prof.XiangjieYang,SchoolofMechanicalEngineering,NanchangUniversity,
China
• Dr.K.M.Kareh,ImperialCollege,London,UK
• JonOlson,Phillips-MedisizeCorporation,USA
• Prof.NobutakaYurioka,Japan
• Prof. S.J. Hong, Division of Advanced Materials Science, Kongju National
University,SouthKorea
• Prof.DonggyuKim,Dong-AUniversity,SouthKorea
TTPandScientificNet(Dr.AndreyLunev),ASMInternational,NADCA,AFS,
TMS, Elsevier,Maney (Routledge,Taylor&Francis Group),Springer,andmany
otherswhoaremissedinthislist.
Wewouldliketoacknowledgethefinancialsupportforsomepartsofourwork
on semi-solid processing ofaluminum alloys which was provided byAlcan Inter-
national(RioTinto-Alcan),NaturalScienceandEngineeringResearchCouncilof
Canada, CQRDA, and the University of Quebec at Chicoutimi, UQAC. In this
regard,weshouldacknowledgethecontributionofProf.AndreCharrette,UQAC,
Prof. Frank Ajersch of Ecole polytechnic de Montreal, Prof. Hojatollah Vali of
McGill University, Dr. Bahadir Kulunk of STAS Inc., and special thanks to Dr.
JosephLanglaisofAlcanforcontinuedsupport.
WearealsogratefultoCanmetMATERIALS,NaturalResourcesCanada/Gov-
ernment of Canada (Drs. Jennifer Jackman, Mahi Sahoo, Daryoush Emadi, and
Mahmoud T. Shehata), for supporting our work on EMS process by providing
accesstoresearchfacilitiesatCanmetMATERIALS.
Finally, the authors would like to acknowledge Prof. Jalal Hedjazi of Iran
University of Science and Technology who was instrumental in motivating the
authorsonsolidificationandcasting.
Edmonton,AB,Canada ShahroozNafisi
Adelaide,SA,Australia RezaGhomashchi
