compound casting - a literature review - YMCA University of Science ...

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Proceedings of the National Conference onTrends and Advances in Mechanical Engineering,YMCA University of Science & Technology, Faridabad, Haryana, Oct 19-20, 2012Table 2 Depicting outcomes of the different reviews• Scanning electronPaper Material Process Major Findings Testing MethodNo.1 Al-Mg Compound • Joining of aluminum andAl 12 Mg 17 intermetallicCastingmagnesium by the compoundcasting process is possible onlymicroscope (SEM).via casting magnesium melt • Energy dispersivearound the aluminum insert, X-ray spectroscopywhile in the case of casting (EDS).aluminum melt around themagnesium insert, a gap is • Wavelengthformed at the interface due to dispersive X-raypresence of oxide layers on thesurface of the aluminum melt andspectroscopy (WDS)detectors.magnesium insert and alsobecause of the interface • X-rayloosening, caused by higher diffractometer.coefficient of thermal expansionof the magnesium insert than the • Push out test.cast aluminum.• Vickers hardness• Formation of the interface in thecompound casting process istester.diffusion controlled and theinterface consists of threedifferent layers.• The layers adjacent to thealuminum and magnesium basemetals are composed of theAl 3 Mg 2 intermetallic compoundand the (Al 12 Mg 17 + ) eutecticstructure, respectively, and themiddle layer is composed of thecompound.2 Titanium/aluminium–siliconTi/Al–7Si–0.3MgInsertMoulding(AluminizingfollowedbyInsertionprocess.)The present paper reports on theapplication of a T6 heat-treatment to thechemically bonded Ti/AS7G bimetallicassemblies.• The results obtained after pushoutand circular bending testshighlight the potential of thisjoining process for producingbimetallic castings with highmechanical strengths.• As expected, the heat treatmentresults in an improvement of themechanical properties of theAS7G matrix itself when appliedto Ti/AS7G assemblies. Asignificant increase of the loadlevel characteristic for damageonset is observed.• This result is of particularinterest, especially whencompared to iron-based inserts inequivalent matrixes, for which a• Optical microscopy(OM).• Scanning electronmicroscopy (SEM).• Energy dispersivespectroscopy (EDS).• Electron probemicroanalysis(EPMA).• Classical push-outtest.• Circular bendingtests• T6-type heattreatment504
3 Al-Al CompoundCastingusing highpressuredie casting4 Mg-MgMagnesiummelt (pureMg or AJ62)is cast onto asolidmagnesiumsubstrate(AZ31) i.e(a)AZ31/AJ62and(b)AZ31/“Mg”compoundsProceedings of the National Conference onTrends and Advances in Mechanical Engineering,YMCA University of Science & Technology, Faridabad, Haryana, Oct 19-20, 2012dramatic weakening of theinterface chemical bond wasnoticed after T6 heat treatment.• After T6 treatment, the shape ofthe Si particles changes fromangular to round as a result of apartial re-dissolution at 540 ◦C.Moreover, the size and number ofthese particles decreasesignificantly in the vicinity of theinsert/alloy interface due to aselective migration of Si towardsthe Ti insert by solid-statediffusion.• The fabrication of an aluminium–aluminium compound wassuccessfully realized by highpressure die casting. Apermanent activation of an Alinsert’s surface was achieved bycombining zincate treatment andzinc galvanizing.• The layer reacts during thecasting process and a continuousmetallic transition forms. Widthas well as microstructure of thetransition zone between matrixand insert varies with varyinginitial layer thickness.CompoundCasting • A pre-treatment technique toenable the wettability of solidmagnesium substrates bymagnesium melts was realized.• By means of laboratory-scalecompound casting experimentsthe reproducible production ofall-magnesium compounds wassuccessfully established.• The newly developed joiningmethod eliminates manydisadvantages of conventionalapproaches, considering galvaniccorrosion, welding depth or lowprocess efficiency.• The coating, an easily depositedmetallic Zn/MgZn2 layer withgood adhesion, is applied viacombiningchemical,electrochemical and heattreatments. It leads to a completechange of the substrate’s surfacereactivity towards Mg melts,providing excellent wettability.• An area-wide, continuouslymetallurgic, defect-free and welldefinedtransition between AZ31505• Optical microscopy.• Scanning electronmicroscopy (SEMPhilips XL30).• The EDX system ofthe SEM are usedfor analysing theelement composition• Hardness testerusing a Vickersindenter.• The tensile tests areperformed with thetensile testingmachine.• Elongation ismeasured with anextensometer• Energy-dispersiveX-ray spectroscopy(EDX).• Scanning electronmicroscope (SEM,Camscan Series 4).• Microhardness.• Differentialscanningcalorimetry
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