Computation of convection and alloy solidification with the software package CrysVUn [Elektronische Ressource] / vorgelegt von Marc Hans Ernst Hainke

Computation of Convection andAlloy Solidi cation with theSoftware Package CrysVUnDer Technischen Fakultat derUniversitat Erlangen-Nurn bergzur Erlangung des GradesDOKTOR-INGENIEURvorgelegt vonMarc Hans Ernst HainkeErlangen 2004Als Dissertation genehmigt vonder Technischen Fakultat derUniversitat Erlangen-Nurn bergTag der Einreichung: 23. Januar 2004Tag der Promotion: 08. Juli 2004Dekan: Prof. Dr. A. WinnackerBerichterstatter: Prof. Dr. G. Mul lerProf. Dr. L. RatkeTo my FamilyManyalloysaresolidifyingwithadendriticcolumnarstructure. Theregion, where solid and liquid phase are co-existent within a certaintemperature interval, is usually called the mushy zone. The resultingmicrostructure is a consequence of transport processes, capillarity ef-fects and thermodynamic constraints. Whereas the theory of purelydiusivesolidi cationisnowadayswelldeveloped,thee ectsofconvec-tive heat and mass transport experience enhanced attention. Thereby,phenomena on di erent length scales are in uenced by convection. Onthe scale of a single dendrite, convection may lead to a changed mor-phology of the dendrites or may even lead to fragmentation. On thescale of the whole sample, convection is mainly responsible for thee ect of macrosegregation.Time dependent magnetic elds are considered as a promising op-tionforsystematicinvestigationsofthee ectsof uid owduringalloysolidi cation.