Interface reaction during titanium alloys investment casting by residue gas in ceramic mold
- 26 Downloads
The chemical reaction between mold material and titanium melt during investment casting was studied intensively. However, the influence of residue gas in ceramic mold on interface reaction remains unclear. In this investigation, the effect of residue gas in Y2O3–silica sol shell mold on interface reaction during Ti–6Al–4V alloy investment casting was investigated. Two groups of shell molds were prepared by adding different kinds of pore formers, i.e., spherical starch particles or nylon fibers, respectively. Ti–6Al–4V alloy was cast under vacuum by gravity casting through cold crucible induction melting (CCIM) method. Porosity of different shell molds was measured based on Archimedean method. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) were employed to characterize the micromorphology and composition of the reaction area, respectively. White light interferometer (WLI) was used to obtain the surface topography of the shell mold. The results show that the direct chemical reaction is very weak for all specimens. The release of residue gas in closed pores is the key factor influencing surface defects. However, open pores make nearly no difference on the interface reaction.
KeywordsTitanium alloy Investment casting Residue gas Y2O3 Silica sol
This study was financially supported by the National Natural Science Foundation of China (No. 50875144).
- Kumar S, Narayanan TNS, Raman SGS, Seshadri SK. Thermal oxidation of Ti6Al4V alloy: microstructural and electrochemical characterization. Mater Chem Phys. 2010;119(1–2):345.Google Scholar
- Liu AH. The interfacial reaction law and micromechanism between titanium alloy melts and ceramic mould. Harbin: Harbin Institute of Technology; 2007. 30.Google Scholar
- Jerry CL, Anthony JF, Eoin JB. Inert calcia facecoats for investment casting of titanium and titanium–aluminide alloys. US Patent; 5766329.1998.Google Scholar
- Neto RL, Duarte TP, Alves JL, Barrigana TG, Da SL. The influence of face coat material on reactivity and fluidity of the Ti6Al4V and TiAl alloys during investment casting. Proc Inst Mech Eng, Part L. 2017;231(1-2):38.Google Scholar
- CamPbell J. Casting (Second Edition). Li DZ, Li YY, translated. Beijing: Science Press, 2011.16.Google Scholar
- Malan AG. Investigation into the continuum thermodynamic modelling of investment casting shell-mould drying. Wales Swansea: University of Wales Swansea; 2003. 10.Google Scholar
- Baghani A, Bahmani A, Davami P, Varahram N, Shabani MO. Application of computational fluid dynamics to study the effects of sprue base geometry on the surface and internal turbulence in gravity casting. Proc Inst Mech Eng, L J Mater Des Appl. 2015;229(12):106.Google Scholar