chapter(3) - Metal Matrix Composites (bilingual teaching)...

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Unformatted text preview: Metal Matrix Composites (bilingual teaching) College of materials science and engineering Jilin University Professor Yu­guang ZHAO Chapter 3, Chapter 3, Interface and compatibility of composites ( 复复复复复复复复复复复复复 ,2 复复 ) (2 class hours) Teaching materials and references 复 [1] Metal Matrix Composites Edited by Karl U. Kainer 2006 WILEY­VCH Verlag GmbH & Co. KGaA, Weinheim ISBN: 3­527­31360­5 [2] Composites manufacturing: materials, product, and process engineering / by Sandjay K. Mazumdar. CRC Press LLC, 2000 N.W. Corporate Blvd., Boca Raton, Florida 33431. [3] Microstructural and mechanical characteristics of in situ metal matrix composites, S.C. Tjong, Z.Y. Ma, Materials Science and Engineering, 29 (2000) 49­113 Reports: A Review Journal. If you have some difficulties to read English teaching materials, you can look up Chinese book as follow: [4] 复复复复复复复,,,,,,,,,,,,,,,,,,,,, 1996 , 7 ,, [5] 复复复复复复复,,,,,,,,,,,,,,,,,, 1995 , 5 ,, Chapter 3, Chapter 3, Interface and Compatibility of composites 复复复复复复复复复复复复 (2class hours) (2class hours) 3.1 Preface( 复复 ) Compared with monolithic materials the microstructure and the interfaces of metal matrix composite materials cannot be considered in isolation, they are mutually related. Chemical interactions and reactions between the matrix and the reinforcement component determine the interface adhesion, modify the characteristics of the composite components and affect the mechanical characteristics significantly. In high temperature use of MMCs the microstructure has to remain stable for long service periods. Thermal stability and failure is determined by changes in the microstructure and at the interfaces, e.g. reaction and precipitation processes. Thermal stress of MMCs can take place both isothermally and cyclically. The effects show differences. During a cyclic load of monolithic materials, especially at high temperature gradients and cycle speeds, a high probability of failure by thermal fatigue is to be expected, e.g. short­fiber reinforced aluminum alloys possess good thermal shock stability. The formation of the interface between the matrix and the reinforcing phase has a substantial influence on the production and characteristics of the metallic composite materials. The adhesion between both phases is usually determined by the interaction between them. During the production of the molten matrix e.g. by infiltration, wettability becomes significant. 复复复复复复 Definition of interface 复 It is a micro­region between matrix and reinforcements where the chemical composition is changed markedly and load can be transferred. It is a new phase which has a certain thickness and structure of which has obvious difference as compared to reinforcement or matrix. So called interfacial phases. 复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复——复复复复 复复复复复复 , 复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复 复复复复复 复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复 复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复 复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复 复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复 复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复 复复复复复复复复复复复 Effect of interface( 复复复复 ) Effect of interface( 1) Transfer effect( 复复复复 ) 复复复复复复复复复复复复复复复复复复复复复 2 复 Interdiction effect( 复复复复 ) 复复复复复复复复复复复复复复复复复复复复复复 3 复 discontinuous effect( 复复复复复 ) 复复复复复复复复复复复复复复复复复复复复复复复 复复复复复复复复复复复复复复复复复复复复复复 4 复 Effects of dispersion and absorption( 复复复复复复 复)复 5 复 Inducement effect( 复复复复 ) 复 复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复 Classification of interface Classification of interface 复复复复复复 ) According to the interaction between matrix and reinforcements MMCs interfaces can be categorised into 3 types ( 复复复复复复复复复复复复复复复复复复复复复复复 ) 复 Type 1——No reaction and no dissolve between matrix and reinforcements.( 复复 1 复复复复复复复复复复复复复复复复 ) For examples: W /Cu, SiC/Al, Al2O3/Cu Type 2——No reaction but dissolving each other (between matrix and reinforcements).( 复复复复复复复复复复复复复复复 ) For examples: W/Nb, C/Ni, W/Cu­Cr Type 3—— reinforcements react with matrix and reactants are formed .( 复复复复复复复复复复复复复复复复 ) For examples: W/Cu­Ti, SiO2/Al, SiC/Ti , W /Cu, SiC/Al, Al2O3/Cu W /Cu, SiC/Al, Al Wetting phenomena( 复复复复 ) Wetting phenomena Basically the wettability of reinforcement with a metal melt can be shown by the edge angle adjustment of a molten droplet on a solid base as the degree of wettability 复复复复复复复复复复复复复复复复复复复复复复复复复复复 according to Young: γSV ­ γSL = γLV cosθ, cosθ = (γSV ­ γSL) / γLV where γ is the surface energy of the liquid phase, LV γ the surface energy of the solid phase, SV γ the interface energy between the liquid and solid SL phases andθis the edge angle. γ — , ­ ,,,,, γ — , ­ ,,,,, SV LV γ — , ­ ,,,,, θ — ,,,,,,,,,, SL ,,, W = γ + γ ­ γ = γ (1+Cosθ) ,,, W = 2γ a LV SV SL LV c LV ,,,, S = W – W , S>0 ,,,,,,,,, a c Figure 3.1 shows the edge angle adjustment of a molten droplet on a solid base for different values of the interface energy. At an angle of >π/2 a nonwettable system is described and for an angle limit of <π/2 a wettable system. With decreasing angle the wettability improves. Fig. 3.1 Edge angle adjustment of a melt drop on a solid base for various values of the interface energy (after Young). γSV ­ γSL = γLV cosθ The adhesion work Wa , immersing work WI , The spreading work WS As the contact develops, for example at the beginning of an infiltration, adhesion occurs. The adhesion work Wa for separation is: Wa( 复复复 ) = γLV + γSV – γSL , Wa = γLV(1+cosθ) Cohesion energy: Wc = 2γ ( 复复复 W = 2γ ) LV c LV Fanning coefficient: S = Wa – Wc ,( 复复复复 S = W – W ) a c when S>0, Wetting phenomena will take place (S>0 复复复复复复复复 ) 复 In the case of immersion the interface between the solid and the atmosphere disappears, while the interface between the solid and the liquid forms. The immersing work Wi is: Wi( 复复复 ) = γLs – γsv In the case of spreading the liquid is spread out on a solid surface. During this procedure the solid surface is reduced as well as a new liquid surface being formed and hence a new solid/liquid interface is formed. The spreading work WS is: WS ( 复复复 ) = γSV – γSL – γLV The wetting procedure is kinetic and is dependent on time and temperature. Therefore, the kinetics can be affected by the temperature. Fig. 3.2 Time dependence of the wetting degree (unit fraction) of SiC plates by aluminum melts at different alloy additions An additional possible influence exists through the change in the surrounding atmosphere or rather the atmosphere in the preform. It is possible, for example, that a preform before infiltration is flushed with gas, which can lead to a change in the oxygen partial pressure. Fig. 3.3 Schematic presentation of the change in the wetting angle with change in the oxygen particle pressure (in the system Al2O3/pure Al) Wetting for the actual infiltration procedure is of substantial importance. This is shown in a simple schematic representation in Fig. 3.4 In the case of good wetting (small edge angle) a capillary effect occurs (Fig. 3.4a). At large edge angles this procedure is inhibited (Fig. 3.4b). Additionally this can occur in technical processes by a reaction between the melt and the surrounding atmosphere. Fig. 3.4 Schematic presentation of an ideal melt infiltration of fiber preforms Means 复 Measures 复 to improve wettability Means ( 复复复复复复复 ) 1 复 Changing the surface state and structure of reinforcements for increasing γSV. Such as mechanical, physical, chemical cleaning; electrochemical treating; polishing ,spreading and so on.( 复复复复复复复复复复复复复复复复 γSV 复复复复复复复复复复复 复复复复复复复复复复复复复复复复复复复复复复复复复复复 ) 2 复 Changing the chemical composition of matrix for depressing γSL. Adding alloy elements into the matrix is the most effectual methods.( 复复复复复复复复复复复复 γSL 复复复复复复复复复复复复复复 ) 3 复 Increasing temperature( 复复复复 ) 复 4 复 Changing environment atmosphere( 复复复复复复 ) 复 5 复 heightening liquid pressure 复 Pc = 4Vt γLVCosθ/dt( 复复复复复复复 Pc = 4Vt γLVcosθ/dt) 6) Some physical methods, Such as ultrasonic, treating by means of several physical field techniques. .( 复复复复复复复复复复复复复复复复复复复复 ) 复 Compatibility of Interface Compatibility of Interface ( 复复复复复复 ) Basic concept: Compatibility of MMCs denotes the concerted extent among constituents of MMCs during the course of processing and using.( 复复复复复复复复复复复复复复复复复复复复复复 复复复复复复复复复复复复复复复 ) 复 复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复 Compatibility of MMCs including( ,,,,,, ) : Physical compatibility( 复复复复复 ): Chemical compatibility( 复复复复复 ): Physical compatibility: Physical compatibility: 复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复 Including: mechanical compatibility and thermal compatibility mechanical compatibility: 复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复 复复复复复复复复复复复复复复复复复复复复 thermal compatibility 复 复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复 复复复复复复复复复复复复复复复复复复复复复复复复 Chemical compatibility: Chemical compatibility: 复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复 Including: thermodynamic compatibility and kinetic compatibility thermodynamic compatibility 复,,,,,,,, 复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复 复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复 复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复 复复复复复复复复复复复复复复复复复复复复复复复复复复复 kinetic compatibility: 复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复 Fracture surfaces in aluminum composite materials after tensile strain vertical to the fiber orientation: (a) fiber/matrix­ delamination (C/Al, weak adhesion); (b) shearing of fibers and dimple formation of a deformed matrix on the fibers (Al2O3/Al­2.5Li, medium adhesion); (c) Fracture in the matrix (SiC/Al good adhesion); (d) fracture run in multiple broken fibers (SiC/Al good adhesion). Binding force and combinative type of Binding force and combinative type of MMCs interface 复复复复复复复复复复复复 Type of interfacial binding force 复 ( 复复复复复复复复 ) 1) Mechanical combining force —— Friction 复 ( 复复复复——复复复 ) 2) Physical combining force —— Van der waals force and hydrogen bond 复 ( 复复复复——复复复复复复复 ) 3) Chemical combining force —— Chemical bond. ( 复复复复——复复复 ) Type of interfacial combination ( 复复复复复复复复复复复复复复复复复复复复复复复复复复复复复 ) 复 Type of interfacial combination Type of interfacial combination 1 复 Mechanical combine( 复复复复 ) 复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复 R/M 复复复复复复 复复复复复复 复复复复复复 2 复 Dissolving and wetting combine( 复复复复复复复 ) 复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复 复复复复复复复复复复复复复复复复复复复 3 复 Reacting combine( 复复复复 ) 复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复 复复复复复复复复复复复复复复复复复复复复复复复复复复复复复 复复复复复复复复复复复复复复复复复复复复复复复复复复复复复 4 复 Combine by exchanging reaction( 复复复复复复 ) 复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复 5 复 Combine by oxide( 复复复复复 ) 复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复 6 复 Mixed combine( 复复复复 ) 复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复 Interfacial residual stress 复复复复复复复 residual thermal stress 复复复复复 residual deformation stress 复复复复复复 residual phase transformation stress 复复复复复复 Stability of interface Stability of interface 复复复复复复 Physical instability factors ,,,,,,, ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, Chemical instability factors ,,,,,,, ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, ,,,,,, Mechanical theory about interface of Mechanical theory about interface of MMCs 复复复复复复复 复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复 复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复 1. Theory of strong interface( 复复复复复 ) 复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复 复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复 复复复复复复复复复复复复复复复复复复复复复 2. Theory of weak interface( 复复复复复 ) 复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复 复复复复复复复复复复复复复复复复复 复复复复复复复复复复复复复复复复 1 复复复复复复复复复复复复复复复复复复复 复复复复 2 复复复复复复复复复复复复复复复复 3 复复复复复复复复复复复复复复复复 复复复复复复复复复复复复复复复 4 复复复复复复复复复复复复复复复复复 复复复复复复复——复复复 1 复复 2 复复复复复复复复复复复复复复复——复复复 3 复 复复复复复复复复复复复复复复复复复——复复复 4 复复复复复复复 Interfacial design about MMCs Interfacial design about MMCs 复复复复复复复复复复复复 复复复复复复复复复复复复复复复复复复复 MMCs 复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复 复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复 R­M 复复复复复复复复复复复复复复复复复复复复复复复 R­M 复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复 复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复复 hybrid reinforcement hybrid reinforcement particle­reinforced brake discs Ex­situ methods, In situ methods Powder metallurgical processes Melting metallurgical processes Infiltration, squeeze casting, vacuum infiltration or pressure infiltration; reaction infiltration of fiber­ or particle preforms Thixocasting, rheocasting, extrusion , forging, compo­casting or melt stirring solid­liquid reaction process vapor­liquid­solid reaction process Self­propagating high­temperature synthesis (SHS) combustion wave thermodynamics and kinetics exothermic dispersion (XD) process reactive hot pressing (RHP) Combustion assisted cast (CAC) ...
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This note was uploaded on 10/15/2011 for the course ENG 209 taught by Professor Zhao during the Spring '10 term at Tsinghua University.

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