scholarly journals Mechanics of elastomeric molecular composites

2018 ◽  
Vol 115 (37) ◽  
pp. 9110-9115 ◽  
Author(s):  
Pierre Millereau ◽  
Etienne Ducrot ◽  
Jess M. Clough ◽  
Meredith E. Wiseman ◽  
Hugh R. Brown ◽  
...  
Keyword(s):  
Soft Materials ◽  
Moderate Level ◽  
Polymer Materials ◽  
High Fracture Toughness ◽  
Dissipated Energy ◽  
High Fracture ◽  
Covalent Bonds ◽  
Volume Fractions ◽  
Bond Scission ◽  
Molecular Composites

A classic paradigm of soft and extensible polymer materials is the difficulty of combining reversible elasticity with high fracture toughness, in particular for moduli above 1 MPa. Our recent discovery of multiple network acrylic elastomers opened a pathway to obtain precisely such a combination. We show here that they can be seen as true molecular composites with a well–cross-linked network acting as a percolating filler embedded in an extensible matrix, so that the stress–strain curves of a family of molecular composite materials made with different volume fractions of the same cross-linked network can be renormalized into a master curve. For low volume fractions (<3%) of cross-linked network, we demonstrate with mechanoluminescence experiments that the elastomer undergoes a strong localized softening due to scission of covalent bonds followed by a stable necking process, a phenomenon never observed before in elastomers. The quantification of the emitted luminescence shows that the damage in the material occurs in two steps, with a first step where random bond breakage occurs in the material accompanied by a moderate level of dissipated energy and a second step where a moderate level of more localized bond scission leads to a much larger level of dissipated energy. This combined use of mechanical macroscopic testing and molecular bond scission data provides unprecedented insight on how tough soft materials can damage and fail.

KAISER ALUMINUM ALLOY 7050

Alloy Digest ◽  
2000 ◽  
Vol 49 (1) ◽  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Tensile Strength ◽  
Aluminum Alloy ◽  
Heat Treating ◽  
High Fracture Toughness ◽  
High Fracture ◽  
Kaiser Aluminum ◽  
Structural Parts ◽  
Very High

Abstract Kaiser Aluminum Alloy 7050 has very high mechanical properties including tensile strength, high fracture toughness, and a high resistance to exfoliation and stress-corrosion cracking. The alloy is typically used in aircraft structural parts. This datasheet provides information on composition, physical properties, hardness, tensile properties, and shear strength as well as fracture toughness and fatigue. It also includes information on forming, heat treating, machining, and joining. Filing Code: AL-366. Producer or source: Tennalum, A Division of Kaiser Aluminum.

FERRIUM M54

Alloy Digest ◽  
2018 ◽  
Vol 67 (9) ◽  
Keyword(s):  
Fracture Toughness ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
High Resistance ◽  
High Strength ◽  
Cost Effective ◽  
High Fracture Toughness ◽  
High Fracture ◽  
Structural Applications ◽  
Resistance To Stress

Abstract Ferrium M54 was designed to create a cost-effective, ultra high-strength, high-fracture toughness material with a high resistance to stress-corrosion cracking for use in structural applications. This datasheet provides information on composition, hardness, and tensile properties as well asfatigue. Filing Code: SA-822. Producer or source: QuesTek Innovations, LLC.

Fracture of Soft Elastic Foam

2015 ◽  
Vol 83 (3) ◽  
Author(s):  
Zhuo Ma ◽  
Xiangchao Feng ◽  
Wei Hong
Keyword(s):  
Fracture Toughness ◽  
Fracture Energy ◽  
Cell Walls ◽  
Scaling Law ◽  
Phase Field Model ◽  
Base Material ◽  
Network Connectivity ◽  
High Fracture Toughness ◽  
High Fracture ◽  
Order Of Magnitude

Consisting of stretchable and flexible cell walls or ligaments, soft elastic foams exhibit extremely high fracture toughness. Using the analogy between the cellular structure and the network structure of rubbery polymers, this paper proposes a scaling law for the fracture energy of soft elastic foam. To verify the scaling law, a phase-field model for the fracture processes in soft elastic structures is developed. The numerical simulations in two-dimensional foam structures of various unit-cell geometries have all achieved good agreement with the scaling law. In addition, the dependences of the macroscopic fracture energy on geometric parameters such as the network connectivity and spatial orientation have also been revealed by the numerical results. To further enhance the fracture toughness, a type of soft foam structures with nonstraight ligaments or folded cell walls has been proposed and its performance studied numerically. Simulations have shown that an effective fracture energy one order of magnitude higher than the base material can be reached by using the soft foam structure.

scholarly journals Investigation into the Structural, Chemical and High Mechanical Reforms in B4C with Graphene Composite Material Substitution for Potential Shielding Frame Applications

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1921
Author(s):  
Ibrahim M. Alarifi
Keyword(s):  
Composite Material ◽  
Melting Point ◽  
Boron Carbide ◽  
High Strength ◽  
Stir Casting ◽  
High Fracture Toughness ◽  
Chemical Compositions ◽  
High Fracture ◽  
Fabrication Procedure ◽  
Standard Designs

In this work, boron carbide and graphene nanoparticle composite material (B4C–G) was investigated using an experimental approach. The composite material prepared with the two-step stir casting method showed significant hardness and high melting point attributes. Scanning electron microscopy (SEM), along with energy dispersive X-ray spectroscopy (EDS) analysis, indicated 83.65%, 17.32%, and 97.00% of boron carbide + 0% graphene nanoparticles chemical compositions for the C-atom, Al-atom, and B4C in the compound studied, respectively. The physical properties of all samples’ B4C–G like density and melting point were 2.4 g/cm3 density and 2450 °C, respectively, while the grain size of B4C–G was in the range of 0.8 ± 0.2 µm. XRD, FTIR, and Raman spectroscopic analysis was also performed to investigate the chemical compositions of the B4C–G composite. The molding press composite machine was a fabrication procedure that resulted in the formation of outstanding materials by utilizing the sintering process, including heating and pressing the materials. For mechanical properties, high fracture toughness and tensile strength of B4C–G composites were analyzed according to ASTM standard designs. The detailed analysis has shown that with 6% graphene content in B4C, the composite material portrays a high strength of 134 MPa and outstanding hardness properties. Based on these findings, it is suggested that the composite materials studied exhibit novel features suitable for use in the application of shielding frames.

scholarly journals Tough metal-ceramic composites with multifunctional nacre-like architecture

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Erik Poloni ◽  
Florian Bouville ◽  
Christopher H. Dreimol ◽  
Tobias P. Niebel ◽  
Thomas Weber ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Sol Gel ◽  
Ceramic Composites ◽  
High Fracture Toughness ◽  
Processing Route ◽  
High Fracture ◽  
Metal Ceramic ◽  
Attractive Option ◽  
Brick And Mortar ◽  
Robotic Applications

AbstractThe brick-and-mortar architecture of biological nacre has inspired the development of synthetic composites with enhanced fracture toughness and multiple functionalities. While the use of metals as the “mortar” phase is an attractive option to maximize fracture toughness of bulk composites, non-mechanical functionalities potentially enabled by the presence of a metal in the structure remain relatively limited and unexplored. Using iron as the mortar phase, we develop and investigate nacre-like composites with high fracture toughness and stiffness combined with unique magnetic, electrical and thermal functionalities. Such metal-ceramic composites are prepared through the sol–gel deposition of iron-based coatings on alumina platelets and the magnetically-driven assembly of the pre-coated platelets into nacre-like architectures, followed by pressure-assisted densification at 1450 °C. With the help of state-of-the-art characterization techniques, we show that this processing route leads to lightweight inorganic structures that display outstanding fracture resistance, show noticeable magnetization and are amenable to fast induction heating. Materials with this set of properties might find use in transport, aerospace and robotic applications that require weight minimization combined with magnetic, electrical or thermal functionalities.

Research on Titanium Alloys with High Toughness and High Damage Tolerance

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.

Technical Basis of Proposed New Acceptance Standards for Class 1, 2 and 3 Piping

2007 ◽  
Author(s):  
Katsumasa Miyazaki ◽  
Kunio Hasegawa ◽  
Naoki Miura ◽  
Koichi Kashima ◽  
Douglas A. Scarth
Keyword(s):  
Fracture Mechanics ◽  
Ultrasonic Inspection ◽  
Limit Load ◽  
Flaw Size ◽  
High Fracture Toughness ◽  
Evaluation Procedure ◽  
High Fracture ◽  
Development Methodology ◽  
Class 1 ◽  
Technical Basis

Acceptance Standards in Section XI of the ASME Boiler and Pressure Vessel Code have an important role as the first step in the flaw evaluation procedure. When a flaw size is within the allowable flaw size in the Acceptance Standard, the flaw is acceptable and analytical evaluation is not required. Although ASME Section XI has Acceptance Standards for Class 1 piping in IWB-3500, there are no Acceptance Standards for Class 2 and 3 piping. Furthermore, the development of the current Acceptance Standards for Class 1 piping was based on flaw detectability by ultrasonic inspection and consideration of fracture mechanics. In this paper, the development of proposed new Acceptance Standards for Class 2 and 3 piping, as well as for Class 1 piping, is described. The development methodology is based on a fracture mechanics approach. For Class 1 piping with high fracture toughness, the allowable flaw sizes were determined by limit load solution. For Class 1 piping, the intent was to maintain overall consistency with the current Acceptance Standards. Proposed Acceptance Standards for Class 2 and 3 austenitic piping were also developed by the methodology used to develop the proposed new Acceptance Standards for Class 1 piping. Allowable flaw sizes for both surface flaws and subsurface flaws for preservice and inservice examinations were developed.

Hypotheses about the Tools Origin of Textile Materials

2015 ◽  
Vol 1090 ◽  
pp. 18-21
Author(s):  
Yuan Tao ◽  
Wei Dong Yu
Keyword(s):  
Soft Materials ◽  
Stone Tools ◽  
Polymer Materials ◽  
Evidence Based ◽  
High Polymer ◽  
Origin Time ◽  
Textile Materials ◽  
Physical Evidence ◽  
Better Than

As high polymer materials, textile materials are easily to be carbonized and then disappear, so it is almost impossible to study the origin of it from physical evidence. Based on the objective historical facts, through analysis and inference, the paper believed that textile materials, as soft materials, are better than stone tools in the aspects of obtaining, making, functions and uses. Two hypotheses about the origin of textile materials are proposed. The first is that textile materials originate from tools, and the origin time of it is not later than stone tools. The second is that signs and clothing application of textile materials both evolve from its usage as tools, so the origin sequence of textile materials is tools, signs, and clothing.

scholarly journals Mechanical Properties of CaO–Al2O3–SiO2 Glass-Ceramics Precipitating Hexagonal CaAl2Si2O8 Crystals

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 393
Author(s):  
Kei Maeda ◽  
Kosho Akatsuka ◽  
Gaku Okuma ◽  
Atsuo Yasumori
Keyword(s):  
Fracture Toughness ◽  
Liquidus Temperature ◽  
Fracture Behavior ◽  
Glass Ceramics ◽  
High Fracture Toughness ◽  
Flexural Test ◽  
Toughening Mechanism ◽  
High Fracture ◽  
X Ray ◽  
Microcrack Toughening

Fracture behavior via a flexural test for a newly found CaO–Al2O3–SiO2 (CAS) glass-ceramic (GC) was compared with that of enstatite GC and mica GC, which are well-known GCs with high-fracture toughness and machinability, respectively. By focusing on the nonelastic load–displacement curves, CAS GC was characterized as a less brittle material similar to machinable mica GC, compared with enstatite GC, which showed higher fracture toughness, KIC. The microcrack toughening mechanism in CAS GC was supported by the nondestructive observation of microcracks around the Vickers indentation using the X-ray microcomputed tomography technique. The CAS GC also showed higher transparency than mica GC due to its low crystallinity. Moreover, the precursor glass had easy formability due to its low-liquidus temperature.

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