Interfacial mechanics of push-out tests: theory and experiments

Abstract:Mechanical properties of Ti/Al-7Si assemblies produced by insert moulding have been studied with a classical push-out test and a variant that is the circular bending test. Special care has been taken for controlling both the reactivity at theTi/Al-7Si interface and the metallurgical health of the Al-7Si matrix. Mechanical tests until complete debonding have been completed with interrupted tests, metallographic characterizations and FEM analysis of elastic stress state. A mean shear strength of the interface of about 120 MPa has been obtained. When the Ti insert is solely fretted in the matrix, without chemical interaction between Ti and the Al-7Si alloy, the mean shear strength is significantly lower (48 MPa). This result clearly shows that chemical interaction at the interface (formation of a thin TiSi layer at the Ti side and a thick Al 3 Ti(Si) layer at the Al-7Si alloy side) improves the mechanical properties of the assembly. It is also shown that the failure sequence is characterized both by crack propagation from bottom to top and matrix yielding from top to bottom. Actually, interface damaging begins by crack initiation at the specimen bottom face (not at the top face, under the indenter) in a nearly pure mode I solicitation at a radial tensile stress of about 100 MPa.

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“…This result is in contrast with failure mechanism usually assumed for push-out experiments in brittle-matrix composites [19][20][21] …”

Section: Finite Element Modelingcontrasting

confidence: 63%

Mechanical testing of titanium/aluminium–silicon interfaces by push-out

et al. 2008

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“…Composite materials contain a large volume fraction of small diameter fibers, which leads to a very large interface area per unit volume (of the order of 10 5 m 2 /m 3 in typical carbon fiber composites). Obviously, composite properties are controlled to large extent by the interface properties and, in particular, interface strength and toughness play a dominant role in the mechanical performance of fiber-reinforced composites.…”

Section: Introductionmentioning

confidence: 99%

“…They use standard composite materials and include the fiber push-out test [7][8][9][10][11][12][13], the slice compression test [14], and the fiber push-in test [15,6,[16][17][18]. The application of the slice compression test to polymer-matrix composites is not obvious while the push-out needs a cumbersome preparation of a very thin membrane (R±50 urn), leading to the fiber push-in test as the best alternative.…”

Section: Introductionmentioning

confidence: 99%

A methodology to measure the interface shear strength by means of the fiber push-in test

Rodríguez

Molina-Aldareguía

González

et al. 2012

Composites Science and Technology

122

104

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A methodology is presented to measure the fiber/matrix interface shear strength in composites. The strategy is based on performing a fiber push-in test at the central fiber of highly-packed fiber clusters with hexagonal symmetry which are often found in unidirectional composites with a high volume fraction of fibers. The mechanics of this test was analyzed in detail by means of three-dimensional finite element simulations. In particular, the influence of different parameters (interface shear strength, toughness and friction as well as fiber longitudinal elastic modulus and curing stresses) on the critical load at the onset of debonding was established. From the results of the numerical simulations, a simple relationship between the critical load and the interface shear strength is proposed. The methodology was validated in an unidirectional C/epoxy composite and the advantages and limitations of the proposed methodology are indicated.

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“…The test intends to assess to which extent the sealer and the core material are bonded together into a solid mass as well as the strength of the bond to the canal wall. Thus, its results can be useful for inferring the stress suffered during post space preparation (8)(9)(10) .So this study was directed to evaluate dentin bond strength by push-out test of three root canal sealers (IRoot SP, AH Plus, and MTA Fillapex endodontic sealers) with cold lateral obturation technique using pushout test.…”

Section: Dentin Bond Strength Evaluation Of Three Root Canal Sealers mentioning

confidence: 99%

Dentin Bond Strength Evaluation of Three Root Canal Sealers with Cold Gutta-Percha Lateral Obturation Technique: Push-Out Test Study

2017

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Aim: This study was designed to evaluate dentin bond strength by push-out test of three root canal sealers (IRoot SP, AH Plus, and MTA Fillapex endodontic sealers) with cold gutta-percha lateral obturation technique using push-out test. Methods: A total of 57 human freshly extracted mandibular premolar teeth for orthodontic reason were used in this study. All samples were decoronated 16±1mm from the apex and prepared using step-back technique up to master apical file # 40. The specimens were divided randomly into three groups (19 teeth each) according to the type of sealers used; Group 1(IRoot SP), Group 2(AH Plus sealer), and Group 3 (MTA Fillapex sealer). Each group was obturated with cold gutta-percha lateral obturation technique. The specimens were incubated for 7 days at 37 o C with 100% humidity. Three sections of 2 mm thickness were obtained at 3, 7 and 11mm from the apex to represent apical, middle and coronal third respectively. The push-out bond strength was determined for each root slice. Values were recorded, tabulated for each group and statistically analyzed. Results: IRoot SP showed the highest mean value of push-out bond strength (7.3±0.2), followed by AH Plus (6.8±0.1) while MTA Fillapex showed the lowest mean value of push-out bond strength (2.9±0.3). Conclusions: IRoot SP and AH plus sealers had greater resistance to push-out than MTA Fillapex sealer.

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Interfacial mechanics of push-out tests: theory and experiments

Cited by 152 publications

References 26 publications

Mechanical testing of titanium/aluminium–silicon interfaces by push-out

Mechanical testing of titanium/aluminium–silicon interfaces by push-out

A methodology to measure the interface shear strength by means of the fiber push-in test

Dentin Bond Strength Evaluation of Three Root Canal Sealers with Cold Gutta-Percha Lateral Obturation Technique: Push-Out Test Study

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