Coupled FEM and Microstructure Modeling Applied to Rolling and Extrusion of Aluminium Alloys

Studies of the mechanisms for buckling and waving in aluminum extrusion by use of a Lagrangian FEM software

“…The choice of using a finite value for _ 0 , and thus an elasto-viscoplastic formulation, is supported by the work of Nes, Marthinsen and co-workers. With their physical based material model, ALFLOW, they have predicted a flow stress as high as 20 MPa after the aluminium leaves the die after extrusion Nes et al, 2002;Marthinsen et al, 2003).…”

“…Nes, Marthinsen and co-workers Nes et al, 2002;Marthinsen et al, 2003) have developed a physically based model which predicts a flow stress as high as 20 MPa at the exit of the die. Such a finite level of flow stress after the outlet implies that it is necessary to include elasticity in the analysis in order to have a correct description of the aluminium after it leaves the die.…”

Novel modelling approach to optimisation of welding conditions and heat treatment schedules for age hardening Al alloys

“…A cross-sectional area of component, m 2 A red reduced cross-sectional area of welded component, m 2 A 0 parameter related to the energy barrier for nucleation, J mol 21 DA necessary increase in cross-sectional area A to maintain the load bearing capacity of the welded component, m 2 b magnitude of the Burgers vector, m C mean solute concentration in matrix, wt-% C 0 nominal content of alloying element, wt-% C e equilibrium solute concentration at the particle/matrix interface, wt-% C i solute concentration at the particle/matrix interface, wt-% C p concentration of element inside the particle, wt-% C Mg equilibrium Mg concentration, wt-% D diffusion coefficient, m 2 s 21 D 0 pre-exponential term in expression for D, m 2 s 21 d plate thickness, m f particle volume fraction F mean interaction force between dislocations and particles, N G shear modulus, N m 22 HV Vickers hardness, VPN DH v enthalpy of vacancy formation, J mol 21 h heat transfer coefficient between the steel backing and the Al plate, W m 22 K j nucleation rate, m 23 s 21 j 0 pre-exponential term in expression for j, m 23 s 21 k i scaling factor in solid solution hardening model (i5Si, Mg, Cu), N m 22 wt-% 2/3 l mean planar particle spacing along the bending dislocation m M Taylor factor Mg 0 ss initial concentration of Mg in solid solution before natural aging, wt-% Mg 0 ss,ref initial concentration of Mg in solid solution in reference alloy before natural aging, wt-% n exponent in natural aging model N a particle number density in the slip plane, m 22 N v number of particles per unit volume, m 23 P tensile or compressive force perpendicular to weld axis, N Q d activation energy for diffusion, J mol 21 q 0 net arc power, W r particle radius, m r mean particle radius, m r* critical particle radius, m r c critical radius for the transition from shearable to non-shearable particles m R universal gas constant 8?314 J Kmol 21 t time, s T temperature, K or uC T L liquidus temperature, K or uC T p peak temperature, K or uC T S solidus temperature, K or uC T ss solutionising temperature, K or uC T Ã ss temperature for full reversion of hardening precipitates in welds, K or uC V mean precipitate volume, m 3 V m molar volume of precipitates, m 3 mol 21 v welding or travel speed, m s 21 w width of component, m w 0 initial width of component, m y m fusion boundary of weld, m y tot total HAZ width, m y eq red ,Dy eq red equivalent half widths of reduced strength zone, m b ratio between the minimum HAZ yield stress and the base metal yield stress b 1 numerical constant in expression for the dislocation line tension c particle/matrix interfacial energy, J m 22 s local HAZ yield stress, N m 22 s b base metal yield stress, N m 22 s i intrinsic yield strength of pure Al, N m 22 s GP strength contribution from GP zones, N m 22 s min minimum HAZ yield stress, N m 22 s p contribution from hardening precipitates to the overall macroscopic yield strength, N m 22 s ss contribution from alloying elements in solid solution to the overall macroscopic yield strength, N m 22 s 0 ss contribution from alloying elements in solid solution to the overall macroscopic yield strength in the as welded condition, N m 22 s wm weld metal yield stress, N m 22 s y overall macroscopic yield strength, N m 22 s \ nominal stress across the weld axis, N m…”

“…The interest in simulation of the response of materials to thermal processing throughout a multistage manufacturing route, commonly referred to as 'through process modelling', has gained considerable momentum over the past decade, both in academia and in industry. [1][2][3][4] This is because there is an increased need for better control of the end product properties, e.g. in fabrication of components and parts for the automotive marked, to meet the customers' requirements.…”

Application of finite element method in the hot extrusion of aluminium alloys

“…A large amount of work in the modelling and simulation of aluminium extrusion processes by the use of FEM has been reported in the last few decades. The applications involve nearly every aspect of the extrusion process: predicting load [1], temperature [2], material flow pattern [3], surface formation [4], surface cracks [5], microstructure [6,7] and isothemal extrusion control [8]. The present paper does not attempt to review the previous work.…”