1 INTRODUCTION TO CENTRIFUGAL CASTING ............................................ 2

1.1 Centrifugal Casting: ......................................................................................................................... 2

1.2 Semi-Centrifugal Casting: ............................................................................................................. 3

1.3 Centrifuging: ....................................................................................................................................... 3

2 MANUFACTURING OF BIMETAL COMPOSITE CYLINDERS FOR AUTOMOTIVE INDUSTRY: ............................................................................................ 4

2.1 Processing of TiB2 containing Aluminium Alloy 2618 [1] ................................................ 4 2.1.1 Processing .......................................................................................................................................... 4 2.1.2 Microstructural Development ......................................................................................................... 5 2.1.3 Mechanical Properties ...................................................................................................................... 5 2.1.4 Thermomechanical Processing ........................................................................................................ 6 2.1.5 Centrifugal Casting ............................................................................................................................ 8 2.1.6 Summary .......................................................................................................................................... 10

2.2 Fine Grained Castings for Single Step Forgings [2] .......................................................... 10 2.2.1 Introduction ..................................................................................................................................... 10 2.2.2 Aluminium + TiB2 .......................................................................................................................... 10 2.2.3 Solidification Micro-Model ............................................................................................................ 11 2.2.4 Solidification Macro-model ........................................................................................................... 12 The micro-model is affected by the heat flow which is calculated by a commercial code (CAP). This model has been coupled to an in-house model to predict shrinkage porosity and mechanical properties in the as cast structure. A series of wedge shapes were cast, and samples tested to validate the models(Fig5). ............................................................................................................................ 12 2.2.5 Modelling the Forging Process ...................................................................................................... 13 The demonstration piece, a piston, is modelled with Forge 3 (Fig6). The constitutive equations governing the deformation of the material are developed from standard mechanical tests. Combining the model results with experimental data will also allow us to develop predictions of the final micro-structure and hence mechanical properties .......................................................................... 13 2.2.6 Thermomechanical Processing ...................................................................................................... 13 Laboratory scale experiments were performed to characterise the alloy behaviour and develop constitutive equations. A double cone specimen was used to show the effect of different amounts of strain (Fig7). The TiB2 appears to restrict the recrystallization of the alloy. Full-scale demonstrator testing of the piston, will be performed at Doncasters. ............................................................................ 13 2.2.7 Conclusions ...................................................................................................................................... 14 2.2.8 Future work ...................................................................................................................................... 14

2.3 Numerical Simulation of Off-Centred Porosity Formation of Ti-Al Based Alloy Exhaust Valve During Vertical Centrifugal Casting [3] ................................................................. 14

2.3.1 Introduction ..................................................................................................................................... 14 2.3.2 Production process of the exhaust valve ...................................................................................... 15 2.3.3 Numerical simulation results ........................................................................................................ 17 2.3.4 Experimental results and discussion ............................................................................................ 22 2.3.5 Conclusions ...................................................................................................................................... 25

3 REFERENCES: ........................................................................................................... 26 [1] M.F. Forster, R. W. Hamilton, R. J. Dashwood and P. D. Lee, Imperial College Department of Materials, Research Project .......................................................................................................................... 26 [2] R. J. Dashwood, P. D. Lee, L. Christodoulou, R. W. Hamilton, M. Forster, Y. Youssef , IMRA Europe, DONCASTERS and LSM, Research Project ................................................................................ 26 [3] Wu Shipping, Guo Jingjie, Su Yanqing, Zhao Chengzie and Jia Jun, Harbin Institute and Technology, School of Materials science and Engineering, Institute of Physics Publishing ............... 26