High Toughness Ceramic Laminates by Design of Residual Stresses

ABSTRACTMultilayered ceramic composites are very promising materials for different engineering applications. Laminates with strong interfaces can provide high apparent fracture toughness and damage tolerance along with the high strength and reliability. The control over the mechanical behavior of laminates can be obtained through design of residual stresses in separate layers. Here we report a development of tough silicon nitride based layered ceramics with controlled compressive and tensile stresses in separate layers. We design laminates in a way to achieve high compressive residual stresses in thin (100-150 micron) Si3N4 layers and low tensile residual stresses in thick (600-700 micron) Si3N4-TiN layers. The residual stresses are controlled by the amount of TiN in layers with residual tensile stresses and the layers thickness. The fracture toughness of pure Si3N4(5wt%Y2O3+2wt%Al2O3) ceramics was measured to be of 5 MPa m1/2, while the apparent fracture toughness of Si3N4/Si3N4-TiN laminates was in the range of 7-8 MPa m1/2 depending on the composition and thickness of the layers.

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Fracture of Ceramics with Near Surface Gradient Residual Stresses

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.333.97 ◽

2007 ◽

Vol 333 ◽

pp. 97-106

Author(s):

Marc Anglada

Keyword(s):

Fracture Toughness ◽

Residual Stresses ◽

Graded Materials ◽

Near Surface ◽

Apparent Fracture Toughness ◽

Surface Gradient ◽

Compressive Stresses ◽

Small Cracks ◽

Monolithic Ceramics ◽

Compressive Residual Stresses

The fracture toughness and strength of ceramics can be improved with respect to monolithic ceramics by developing graded materials as laminates composed of periodic alternating layers of one material separated by layers of a second material. The second layer must contain residual compressive stresses which are induced during densification because of differential thermal contraction of the layers. The overall residual stresses increase the apparent fracture toughness of the laminate. However, most deleterious natural flaws and most of the damage induced in service by the environment, contact loading, wear, etc, are small cracks on the surface of the outer layer, so that the effect of the laminate residual stresses on these cracks should be rationalised to understand their behaviour. This work presents an analysis of the influence of the gradient residual stresses on the behaviour of surface cracks under bending and indentation in materials with outer layers either with tensile or compressive residual stresses.

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Failure Behaviour of High Toughness Multi-Layer Si3N4 and Si3N4-TiN Based Laminates

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.290.175 ◽

2005 ◽

Vol 290 ◽

pp. 175-182 ◽

Cited By ~ 5

Author(s):

Gurdial Blugan ◽

Richard Dobedoe ◽

I. Gee ◽

Nina Orlovskaya ◽

Jakob Kübler

Keyword(s):

Fracture Toughness ◽

High Temperature ◽

Residual Stresses ◽

Crack Propagation ◽

Failure Mechanisms ◽

High Strength ◽

Crack Deflection ◽

High Toughness ◽

Energy Absorbing ◽

Crack Bifurcation

Multi-layer laminates were produced using alternating layers of Si3N4 and Si3N4+TiN. The differences in the coefficient of thermal expansions between the alternating layers lead to residual stresses after cooling. These are compressive in the Si3N4 layers and tensile in the Si3N4+TiN layers. The existence of these stresses in the laminates effect the crack propagation behaviour during failure. Different designs of laminates were produced with external layers under compression and tension exhibiting different failure mechanisms. Facture toughness was measured by SEVNB method. In systems with external layers under compression the measured fracture toughness was up to three times that of Si3N4, i.e. up to 17 MPa m1/2. In systems with external layers under tension during failure the energy absorbing effects of crack deflection and crack bifurcation were obtained. High temperature tests were performed to determine the onset temperature for residual stresses in these laminates. Micro-laminates with compressive layers of only 30 µm thickness with high strength and fracture toughness and were manufactured.

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The Effect of Surface Enhancement on Improving the Fatigue and Sour Service Performance of Downhole Tubular Components

Volume 3: Design, Materials and Manufacturing, Parts A, B, and C ◽

10.1115/imece2012-87482 ◽

2012 ◽

Author(s):

Jeremy E. Scheel ◽

Douglas J. Hornbach

Keyword(s):

Carbon Steel ◽

Residual Stresses ◽

High Strength ◽

Steel Alloys ◽

Surface Enhancement ◽

Tensile Stresses ◽

High Magnitude ◽

Sour Service ◽

Tubular Components ◽

Compressive Residual Stresses

Sulfide stress cracking (SSC) and hydrogen embrittlement (HE) prevent the use of high strength carbon steel alloys in the recovery of fossil fuels in H2S containing ‘sour’ environments commonly experienced in deep well fossil fuel recovery efforts. Couplings are a common weak point in casing strings as high magnitude mean tensile stresses are generated by connection interferences created during power make-up of downhole tubular components. When subject to service loads both mean and alternating stresses are increased further providing the high tensile stresses necessary for SSC initiation. Since high strength carbon steel alloys are not typically suited for sour service environments, the current solution is to use or develop much more expensive alloys with increased corrosion-cracking resistance, or limit their use to significantly weaker sour environments, or higher operating temperatures. Failure due to fatigue is another major problem in downhole tubular components. Likelihood of fatigue failure is further exacerbated in corrosive environments (such as H2S and NaCl), commonly encountered in service. The cost for detecting the impending failure before final separation is dramatic at a factor 10X. A cost effective method of mitigating failure from SSC and corrosion fatigue would greatly reduce operational costs and extend component life. Introduction of stable, high magnitude compressive residual stresses into less expensive carbon steel alloys alleviates the tensile stresses, and mitigates SSC, while also improving fatigue performance. Low plasticity burnishing (LPB) is an advanced surface enhancement process providing a means of introducing compressive residual stresses into metallic components for enhanced fatigue, damage tolerance, and SCC performance. The effects of LPB on high cycle fatigue (HCF) and SSC were evaluated on quench and tempered API P110 grade steel. LPB processed specimens had an increase in fatigue life greater than an order of magnitude over untreated specimens. LPB was successful in completely mitigating SSC in all test specimens at tensile stresses up to 90% specified minimum yield strength (SMYS). The initial results indicate that LPB processing of P110 steel provides an economical means of SSC mitigation and fatigue strength improvement in sour environments.

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DILLIMAX 500

Alloy Digest ◽

10.31399/asm.ad.sa0645 ◽

2012 ◽

Vol 61 (3) ◽

Keyword(s):

Fracture Toughness ◽

Yield Strength ◽

Physical Properties ◽

Structural Steel ◽

Tensile Properties ◽

High Strength ◽

Heat Treating ◽

Fine Grained ◽

High Toughness ◽

Minimum Yield

Abstract Dillimax 500 is a high-strength quenched and tempered, fine-grained structural steel with a minimum yield strength of 500 MPa (72 ksi). Plate is delivered in three qualities: basic, high toughness, and extra tough. This datasheet provides information on composition, physical properties, and tensile properties as well as fracture toughness. It also includes information on surface qualities as well as forming, heat treating, and joining. Filing Code: SA-645. Producer or source: Dillinger Hütte GTS.

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TLS S1

Alloy Digest ◽

10.31399/asm.ad.ts0655 ◽

2007 ◽

Vol 56 (9) ◽

Keyword(s):

Fracture Toughness ◽

Wear Resistance ◽

Physical Properties ◽

Carbon Content ◽

High Strength ◽

Heat Treating ◽

High Toughness

Abstract The carbon content in TLS S1, about 0.5%, produces a combination of high strength and high toughness with medium wear resistance. Chisels and rivet sets are typical applications. This datasheet provides information on composition, physical properties, hardness, and elasticity as well as fracture toughness. It also includes information on wear resistance as well as heat treating and machining. Filing Code: TS-655. Producer or source: Timken Latrobe Steel.

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Research on Titanium Alloys with High Toughness and High Damage Tolerance

Materials Science Forum ◽

10.4028/www.scientific.net/msf.618-619.97 ◽

2009 ◽

Vol 618-619 ◽

pp. 97-100

Author(s):

Yong Qing Zhao ◽

Heng Lei Qu ◽

Jun Chen

Keyword(s):

Damage Tolerance ◽

Rapid Development ◽

Crack Propagation Rate ◽

High Strength ◽

High Fracture Toughness ◽

Ti Alloy ◽

Chinese Market ◽

High Fracture ◽

High Toughness ◽

Ti Alloys

The recent shift in the design focus for aeroplanes from strength to damage tolerance has led to a subsequent shift in the focus of Ti alloy research. China first started to research Ti alloys with damage tolerance from the year 2000. The first product stemming from this research is a Ti alloy with high strength, high toughness and damage tolerance (TC21). TC21 exhibits high strength (UTS  1100MPa), high fracture toughness (K1c  70MPa.m1/2) and a low crack propagation rate (da/dN being similar to Ti-6-4 with  annealing). Another Ti alloy, named TC4-DT, has also been produced. It has moderate strength, along with high toughness and damage tolerance (UTS  900MPa, K1c  70MPa.m1/2, da/dN being similar to Ti-6-4 with  annealing). Both TC21 and TC4-DT are now undergoing rapid development, with the former alloy also being applied to a full scale aeronautical application. Both TC21 and TC4-DT have promising futures in the industry. They will be the main Ti alloys with damage tolerance utilised in the Chinese market.

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Influence of the Interface and Residual Stresses on the Apparent Fracture Toughness of Layered Ceramic Composites Based on Alumina-Zirconia

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.606.209 ◽

2014 ◽

Vol 606 ◽

pp. 209-212

Author(s):

Luboš Náhlík ◽

Bohuslav Máša ◽

Pavel Hutař

Keyword(s):

Residual Stresses ◽

Crack Propagation ◽

Ceramic Composites ◽

Layered Composites ◽

Material Interfaces ◽

Linear Elastic ◽

Apparent Fracture Toughness ◽

Elastic Fracture ◽

Layered Ceramic ◽

Good Agreement

This paper deals with the fracture behaviour of layered ceramic composite with residual stresses. The main goal is to investigate the effect of residual stresses and material interfaces on crack propagation by more complex 3D finite element models. The crack behaviour was described by analytical procedures based on linear elastic fracture mechanics (LEFM) and generalized LEFM. The influence of laminate composition with residual stresses on critical values for crack propagation through the laminate interfaces was also determined. Good agreement has been found to exist between numerical results and experimental data. The results obtained can be used for a design of new layered composites with improved resistance against crack propagation.

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Short Crack Propagation Model Applied to Shot Peened Aluminium Alloys

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.65.53 ◽

2009 ◽

Vol 65 ◽

pp. 53-61 ◽

Cited By ~ 2

Author(s):

J. Solis ◽

J. Oseguera-Peña ◽

I. Betancourt

Keyword(s):

Surface Roughness ◽

Residual Stresses ◽

Crack Propagation ◽

Aluminium Alloys ◽

Micromechanical Model ◽

High Strength ◽

Crack Arrest ◽

Propagation Model ◽

Safe Load ◽

Compressive Residual Stresses

The Navarro-Rios micromechanical model was used to assess the bounds of two different damage zones: crack arrest region and crack propagation region of controlled shot peening (CSP) of high strength aluminium alloys. Performance of CSP in terms of fatigue resistance was investigated. This comparison indicated that CSP in terms of fatigue depends on the competition between its beneficial and detrimental products, i.e. surface roughness and compressive residual stresses respectively. The gathered information can be used for safe load determinations in design.

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Strong Interface in CMCs, a Condition for Efficient Multilayered Interphases

MRS Proceedings ◽

10.1557/proc-365-371 ◽

1994 ◽

Vol 365 ◽

Cited By ~ 23

Author(s):

Christine Droillard ◽

Jacques Lamon ◽

Xavier Bourrat

Keyword(s):

Fracture Toughness ◽

Bonding Strength ◽

High Strength ◽

Interfacial Behavior ◽

Strain Behavior ◽

High Toughness ◽

Sic Fiber ◽

Sliding Mechanism ◽

Fiber Treatment ◽

Sic Composites

ABSTRACTA fiber treatment was used to change the bonding strength of the Nicalon NLM 202 SiC fiber from weak to strong, in a series of 2D-SiC/SiC composites with multilayered interphases. The materials with the pre-treated fibers were compared to the same materials but reinforced with as received fibers. The stress-strain behavior and the fracture toughness were examined as a function of crack patterns identified by TEM. All the materials could be grouped into two distinct families: (i) materials reinforced with untreated fibers have a weak fiber bonding and are characterized by a low strength and a low toughness and (2) materials with the pre-treated fibers have a strong fiber bonding and are characterized by a high strength and a high toughness. This latter behavior is identified by TEM. It corresponds to a new interfacial behavior with a cohesive mode of interfacial cracking, involving branching and deflection by the successive interfaces. In the former family, the adhesive interfacial failure mode corresponds to the classical debond/sliding mechanism.

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