THE TRANSVERSE CREEP AND TENSILE BEHAVIOUR OF SCS-6/Ti-6Al-4V METAL MATRIX COMPOSITES AT 482°C

Eggleston, M. R.; Krempl, E.

doi:10.1080/10759419408945821

Cited by 19 publications

(4 citation statements)

References 10 publications

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“…While reasonable agreement is achieved with Eggleston's model, a broad range in composite response could be modeled equally well by varying the proportion of weak and strong interfaces and their distribution in the composite (Figure 15 in Ref. 11), so that these predictions are not particularly discriminating.…”

Section: Resultsmentioning

confidence: 98%

“…[2,[5][6][7][8][9][10][11] Results from these studies showed that the minimum creep rate of the TMC was nearly always higher than that of the unreinforced matrix, or that the time to failure was shorter for the TMC. The models used to represent transverse creep have generally assumed that the interface has no intrinsic strength, and separation occurs as soon as the local mechanical stress is sufficient to overcome the residual thermal stresses.…”

Section: Introductionmentioning

confidence: 99%

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Transverse creep of SiC/Ti-6Al-4V fiber-reinforced metal matrix composites

Miracle

Majumdar

1999

Metall Mater Trans A

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The transverse creep response of an 8-ply SiC (SCS-6)/Ti-6Al-4V composite was measured at 482 ЊC from 69 to 276 MPa. Creep samples with fibers exposed at the edges as well as specimens with fully embedded fibers were tested under stepped loading conditions with increasing load. The response of each sample geometry was compared with creep data from the unreinforced matrix ('neat' material). The samples with exposed fiber ends exhibited minimum creep rates that were higher than those of the neat material at all stresses, and the stress exponent was slightly larger than the neat material. The embedded fiber samples possessed minimum creep rates that were smaller than the neat material at low stresses (Ͻ115 MPa), but became equivalent to the exposed fiber data at the highest stress (276 MPa). The apparent stress exponent for the embedded fiber composite was significantly larger than the neat material. The exposed fiber test data were well represented by a standard Crossman analysis, where the fibers were considered to have completely debonded. A stress singularity in the interfacial region at the sample edge is responsible for this behavior. The Crossman model was modified to incorporate the effect of a finite interface strength (120 MPa), and this was used to describe the response of the samples with embedded fibers. A reasonable fit to this representation was obtained. However, the measured minimum creep rate at the lowest stress was significantly lower than that predicted by the Crossman analysis for fully bonded fibers.

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Section: Resultsmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Transverse creep of SiC/Ti-6Al-4V fiber-reinforced metal matrix composites

Miracle

Majumdar

1999

Metall Mater Trans A

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“…Several interface models such as fully bonded [3,4], completely debonded [3,[5][6][7], stiff springs elements [8,9] and flexible interface [10,11] have been utilized in the earlier studies. In the present study, a weak interface is implemented by introducing the cohesive zone model along the boundary between the fiber and coating.…”

Section: Interface Modelmentioning

confidence: 99%

“…To start with, perfectly bonded [3,4] and completely debonded [3,[5][6][7] interfaces have been applied for various types of loadings which over and under-estimates the strength of composites. These two models cannot predict the behavior of the MMCs under transverse and axial shear loadings, so that interface models considering the damage of the interface are presented.…”

Section: Introductionmentioning

confidence: 99%

Simulation of interface damage in metal matrix composites under off-axis loading using cohesive zone model

Aghdam

Hosseini

Morsali

2015

Computational Materials Science

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Prediction of Damage Evolution in Continuous Fiber Metal Matrix Composites Subjected to Fatigue Loading

Allen

Helms

Hurtado

et al. 1995

Contemporary Research in Engineering Science

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RECEIVEDbecause the material parameters do not appear to be available for other models.In the current paper, the fiber i s assumed to be thennoelastic (E; =O>. Assuming that the temperature field is known (from conservation of energy), the above field equatiom c8z1 be cast with appropriate mechanical boundary conditions to produce a well-posed boundary value problem.?"ne the.rmomechanical model proceeds fkorn the application of continuum thermomechanics t o a thermoviscoplastic medium [90]. Due to thc nonlinearities introduced by the thermoviscoplastic constitutive model, analytic solutians are not practical for most geometries and loading conditions. Therefore, the solutions are obtained computationally via the finite element method.The details of the formulation are given in Allen, et ai-[38] and Jeong, et d. [IO], Briefly, the conservation of momentum (1) is cast into a weak variational principle in terms of the primary variable uiAui(a,t)-This variational principle is incremented in time, and the straiq4splscement equation (2) and constitutive equations (3) are substituted to obtain a field problem which can be discretized for a typical finite element. Due t o the fact that internal variable evolution equations (4) are ordinary differential equations, the variational principle must be incremented in time, and the solution is obtained by incrementing &e boundary data with time. Due to.the nonlinearity of evolution equations (4) (they are actually numerically Stiff), extremely small time steps are required in order t o obtain accurate solutions, s o that for cyclic loading thc solution is computationally intensive. As described in the section on crack growth, this problem may be exacerbated by instabilities introduced during periods of crack propagation.The oxidation model proceeds from the assumption that the rnks of oxygen is conserved within the solid MMC. This produces a diffusion modd for the species of owgen, c=c(xk,t), of the f o m :' 0 7 / 1 2 / 9 5 1 1 : 0 9 B 1 0 9 815 6 0 5 1 Mare recently, the algorithm has been used to predict the effects of surface oxidation on the response of the composite. Although the &hate objective of this effort is to use the algorithm t o predict the effect of oxidation on We, we have not yet proceeded this far. Thus, we will report only prehinary results herein. Using the unit cell shown in Fig. 9, a plane strain analysis has been performed for a monotonically increashg displacement applied normal t o the fiber direction. As shown i n Fig. 11, i;his analysis has been performed for h o cases: a specimen that is assumed t o be unorridizcd, and a specimen that is assumed t o have been pre-oxidized with a surface oxide layer of 50 micron thickness. It is seen in t h e figure that the average stress-strain behavior of the composite is deteriorated in the oxidized case-The reason for this can be explained by triewing Fig. 12, wherein the crack length is platted versus time.As can be seen, the development of surface cracks in the oxidized specimen tends to shed load to the in...

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THE TRANSVERSE CREEP AND TENSILE BEHAVIOUR OF SCS-6/Ti-6Al-4V METAL MATRIX COMPOSITES AT 482°C

Cited by 19 publications

References 10 publications

Transverse creep of SiC/Ti-6Al-4V fiber-reinforced metal matrix composites

Transverse creep of SiC/Ti-6Al-4V fiber-reinforced metal matrix composites

Simulation of interface damage in metal matrix composites under off-axis loading using cohesive zone model

Prediction of Damage Evolution in Continuous Fiber Metal Matrix Composites Subjected to Fatigue Loading

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