Self-Healing Materials as New Biologically Inspired Materials

2012 ◽  
Vol 16 ◽  
pp. 11-25
Author(s):  
Fabrizia Ghezzo ◽  
Xi Geng Miao
Keyword(s):  
Failure Mechanisms ◽  
Matrix Material ◽  
High Strength ◽  
Self Healing ◽  
Micro Cracks ◽  
Specific Objective ◽  
Wide Range ◽  
The Matrix ◽  
Safety And Reliability ◽  
Healing Agent

Lightweight, high strength fibre-reinforced polymeric composites are leading materials in many advanced applications including biomedical components. These materials offer the feasibility to incorporate multi functionalities due to their internal architecture, heterogeneity of materials and the flexibility of combining them using currently available fabrication methods. In spite of the excellent properties of these materials, their failure is still a questionable and not well predicted event. Delamination, debonding and micro-cracks are only some of the failure mechanisms that affect the matrices of polymer based composites. More complex cases exist with the combination of multiple failure mechanisms. In such cases a self-repairing mechanism that can be auto-triggered in the matrix material once the crack has been formed, would be very beneficial for all the applications of these materials, reducing maintenance costs and increasing their safety and reliability. Self-healing materials have been studied for more than a decade by now, with the specific objective of reducing the risks and costs of cracking and damage in a wide range of materials. Different approaches have been taken to create such materials, depending on the kind of material that needs to be repaired. The most popular methods developed for polymers and polymer reinforced composites are considered in this review. These methods include materials with micro-capsules containing a healing agent, and composites with matrices that can self-heal the cracks by repairing the broken molecular links upon external heating. While the first approach to healing has been widely used and studied in the past decade, in this review we focus on the second approach since less is reported in the literature and more difficult is the development of the materials based on such a method.

Novel Self-Healing Systems: Expanding and Inhibited Healing Agents

2014 ◽  
Author(s):  
S. I. Rae ◽  
I. P. Bond ◽  
R. S. Trask ◽  
D. F. Wass
Keyword(s):  
Matrix Material ◽  
Fibre Reinforcement ◽  
Self Healing ◽  
New Approach ◽  
Healing Efficiency ◽  
Mechanical And Physical Properties ◽  
The Matrix ◽  
Healing Agent ◽  
To Come ◽  
And Performance

A new approach to self-healing systems is presented that aims to overcome the inherent drawbacks of conventional liquid resin based healing systems within composites. Finite embedded systems offer limited healing potential for small volume delaminations and as such cannot effectively heal large damage volumes often associated with shear damaged sandwich panel structures or debonding between skin and core. An expanding polymer based approach aims to overcome such limitations. The mechanical and physical properties of a prepared polyepoxide foam are investigated and how the inclusion of a carbon fibre reinforcement within the foam affects processability and performance. The healing efficiency of different polymer foams to heal damaged structures is also investigated. A secondary investigation is also presented that aimed to overcome the drawbacks associated with the requirement for stoichiometric mixing of two part healing agents, or for healing agent to come into direct contact with a catalyst embedded within the matrix material. Different approaches were taken to develop a self-healing system that once deployed required no additional mixing or stimuli for healing to occur.

Mechanical responses of microencapsulated self-healing cementitious composites under compressive loading based on a micromechanical damage-healing model

2021 ◽  
pp. 105678952110112
Author(s):  
Kaihang Han ◽  
Jiann-Wen Woody Ju ◽  
Yinghui Zhu ◽  
Hao Zhang ◽  
Tien-Shu Chang ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Compressive Strength ◽  
Micromechanical Model ◽  
Cementitious Composites ◽  
Self Healing ◽  
Damage Degree ◽  
Healing Efficiency ◽  
The Matrix ◽  
Healing Agent ◽  
Damage Healing

The cementitious composites with microencapsulated healing agents have become a class of hotspots in the field of construction materials, and they have very broad application prospects and research values. The in-depth study on multi-scale mechanical behaviors of microencapsulated self-healing cementitious composites is critical to quantitatively account for the mechanical response during the damage-healing process. This paper proposes a three-dimensional evolutionary micromechanical model to quantitatively explain the self-healing effects of microencapsulated healing agents on the damage induced by microcracks. By virtue of the proposed 3 D micromechanical model, the evolutionary domains of microcrack growth (DMG) and corresponding compliances of the initial, extended and repaired phases are obtained. Moreover, the elaborate studies are conducted to inspect the effects of various system parameters involving the healing efficiency, fracture toughness and preloading-induced damage degrees on the compliances and stress-strain relations. The results indicate that relatively significant healing efficiency, preloading-induced damage degree and the fracture toughness of polymerized healing agent with the matrix will lead to a higher compressive strength and stiffness. However, the specimen will break owing to the nucleated microcracks rather than the repaired kinked microcracks. Further, excessive higher values of healing efficiency, preloading-induced damage degree and the fracture toughness of polymerized healing agent with the matrix will not affect the compressive strength of the cementitious composites. Therefore, a stronger matrix is required. To achieve the desired healing effects, the specific parameters of both the matrix and microcapsules should be selected prudently.

Self-healing organic coatings based on microcapsules – A patent-based review

2021 ◽  
Vol 04 ◽  
Author(s):  
Diego Moreira Schlemper ◽  
Sérgio Henrique Pezzin
Keyword(s):  
Corrosion Protection ◽  
State Of The Art ◽  
Review Article ◽  
The State ◽  
Organic Coatings ◽  
Self Healing ◽  
Future Challenges ◽  
The Matrix ◽  
Healing Agent

: Self-healing coatings are intended to increase long-term durability and reliability and can be enabled by the presence of microcapsules containing a self-healing agent capable of interacting with the matrix and regenerating the system. This review article provides an overview of the state-of-the-art, focusing on the patents published in the field of microcapsule-based self-healing organic coatings, since the early 2000’s. A discussion about coatings for corrosion protection and the different self-healing approaches and mechanisms are also addressed, as well as future challenges and expectations for this kind of coatings.

Advanced Fiber Reinforced Self-Healing Ceramics for Middle Range Temperature

2019 ◽  
Vol 810 ◽  
pp. 119-124
Author(s):  
Wataru Nakao ◽  
Taira Hayakawa ◽  
Tesuro Yanaseko ◽  
Shingo Ozaki
Keyword(s):  
Low Temperature ◽  
Turbine Blade ◽  
The Self ◽  
Self Healing ◽  
Fiber Reinforced ◽  
Low Pressure Turbine ◽  
Middle Range ◽  
The Matrix ◽  
Healing Agent ◽  
Technical Issues

The availability of TiC healing agent has been evaluated in low temperature self-healing behavior of Al2O3 based self-healing ceramics. For this purpose, some technical issues to actualize the advanced fiber-reinforced self-healing ceramics containing TiC based interlayer as healing agent were discussed. Especially, the mechanical matching between the matrix and the interlayer was focused. Moreover, the self-healing behavior of the advanced shFRC containing the optimized TiC based healing agent was investigated. As a result, 30 vol% TiC-70 vol% Al2O3 interlayer was confirmed to be the optimized healing agent in the self-healing ceramics, and the self-healing ceramics was found to enable to attain the perfect healing at 600°C within 10 min. And we succeeded in prototype production of fiber-reinforced self-healing ceramics for low pressure turbine blade.

Investigation of Tensile Property of Aluminium SiC Metal Matrix Composite

2015 ◽  
Vol 766-767 ◽  
pp. 252-256 ◽  
Author(s):  
A. Siddique Ahmed Ghias ◽  
B. Vijaya Ramnath
Keyword(s):  
Composite Material ◽  
Metal Matrix Composite ◽  
Matrix Composite ◽  
Metal Matrix ◽  
Matrix Material ◽  
Chemical Properties ◽  
High Strength ◽  
Stir Casting ◽  
The Matrix ◽  
Hybrid Metal Matrix Composite

The composite material is a combination of two or more materials with different physical and chemical properties. The composite has superior characteristics than those individual components. A hybrid composite is the one which contains at least three materials. When the matrix material is a metal, the composite is termed as metal matrix composites (MMC). The MMC is a composite material with two constituent parts, one being a metal. The other material may be another metal, ceramic or fiber. Among all the MMC’s, Aluminium is the most widely used matrix material due to its light weight, high strength and hardness. This paper deals with the fabrication and mechanical investigation of hybrid metal matrix composite Al - SiC. The fabrication is done by stir casting by adding the required quantities of additives into the stirred molten Aluminium. The results show significant effect of mechanical properties such as tensile strength, yield stress and flexural strength. The internal structure of the composite is observed using Scanning electron microscope (SEM) and found that are formation of pores in them.

scholarly journals Recent studies on particulate reinforced AZ91 magnesium composites fabricated by Stir casting – A review

2020 ◽  
Vol 4 (2) ◽  
pp. 115-126
Author(s):  
Anil K. Matta ◽  
Naga S. S. Koka ◽  
Sameer K. Devarakonda
Keyword(s):  
High Performance ◽  
Matrix Material ◽  
Weight Ratio ◽  
High Strength ◽  
Casting Process ◽  
Stir Casting ◽  
Critical Conditions ◽  
Matrix Composites ◽  
The Matrix ◽  
Magnesium Composites

Magnesium Metal Matrix Composites (Mg MMC) have been the focus of consideration by many researchers for the past few years. Many applications of Mg MMCs were evolved in less span of time in the automotive and aerospace sector to capture the benefit of high strength to weight ratio along with improved corrosion resistance. However, the performance of these materials in critical conditions is significantly influenced by several factors including the fabrication methods used for processing the composites. Most of the papers addressed all the manufacturing strategies of Mg MMC but no paper was recognized as a dedicated source for magnesium composites prepared through stir casting process. Since stir casting is the least expensive and most common process in the preparation of composites, this paper reviews particulate based Mg MMCs fabricated with stir casting technology. AZ91 series alloys are considered as the matrix material while the effect of different particle reinforcements, sizes , weight fractions on mechanical and tribological responses are elaborated in support with micro structural examinations. Technical difficulties and latest innovations happened during the last decade in making Mg MMCs as high performance material are also presented.

scholarly journals Micromechanical evaluation of failure models for unidirectional fiber-reinforced composites

2019 ◽  
Vol 54 (6) ◽  
pp. 791-800
Author(s):  
Azam Arefi ◽  
Frans P van der Meer ◽  
Mohammad Reza Forouzan ◽  
Mohammad Silani ◽  
Mahmoud Salimi
Keyword(s):  
Matrix Material ◽  
Element Model ◽  
Failure Criteria ◽  
Fiber Reinforced Composites ◽  
Fiber Direction ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Wide Range ◽  
The Matrix ◽  
Stress States

In this paper, micromechanical simulations are employed to evaluate the performance of the Tsai–Wu and Hashin failure criteria for fiber-reinforced composites, especially in stress states whose experimental reproduction is complicated. Micromechanical responses are generated using a finite element model of a representative volume element, in which only the matrix material experiences damage and the fibers are assumed to be elastic. Micromechanical simulations of basic load cases are used to calibrate macrolevel criteria. Finally, the response of the micromodel and macromodels is compared for various load combinations. Despite a good agreement between Tsai–Wu criterion predictions and micromodel results in a wide range of stress states, some stress combinations are highlighted for which the strength is not predicted accurately. Additionally, accuracy of the Hashin criterion suffers from ignoring the influence of stress in fiber direction on matrix failure.

Measurement of microscopic displacements in graphite/epoxy composite materials using a SEM-generated surface map

1990 ◽  
Vol 48 (4) ◽  
pp. 430-431
Author(s):  
R.C. Burghardt ◽  
J.M. Ehrman ◽  
T.C. Stephens ◽  
M.F. Hibbs
Keyword(s):  
Composite Materials ◽  
Resin Composite ◽  
Matrix Material ◽  
Crack Tip ◽  
High Strength ◽  
Beam Current ◽  
Experimental Conditions ◽  
X Ray ◽  
The Matrix ◽  
Sporting Goods

Graphite fiber-reinforced resin composite materials have a wide use in aerospace, automotive and sporting goods applications where high strength to weight ratios are requisite. Many of these materials use highly cross-linked epoxy resins as the matrix material. Unfortunately these resins have a low resistance to crack propagation and as a result research efforts have been directed towards reducing this tendency.The ability to measure microscopic displacements and calculate strain fields in the vicinity of a fracture crack tip under experimental conditions was needed in order to help predict the fracture resistance of various composite materials being tested. A technique was developed that made it possible to derive displacement measurements on a micrometer scale in the region of a crack tip from observations of epoxy-based composites being fractured using a tensile stage equipped scanning electron microscope (SEM). Samples were polished on the surface to be observed and sputter coated with 5 to 10 nanometers of either gold or 60:40 gold-palladium prior to mounting on the TS-2 tensile stage of a JEOL JSM-35CF. This instrument was also equipped with a Krisel beam interceptor, a beam current meter, a Tracor Northern TN-2000 x-ray analyzer and a TN-1310 digital beam control system. Using the digital beam and x-ray mapping capabilities a matrix of small dots was “written” onto the surface of the sample as shown in figure 1.

Aero-Engine Titanium from Alloys to Composites

2009 ◽  
Vol 618-619 ◽  
pp. 127-134 ◽  
Author(s):  
Phill Doorbar ◽  
Mark Dixon ◽  
Amit Chatterjee
Keyword(s):  
Titanium Alloys ◽  
Raw Materials ◽  
High Strength ◽  
Application Development ◽  
Alloy Development ◽  
Wide Range ◽  
Aero Engine ◽  
Temperature Capability ◽  
The Matrix ◽  
Imi 834

The aero-engine has provided the major drive for the development of new improved titanium alloys in recent years. This paper covers these developments from the workhorse alloy Titanium 6/4 and it’s higher temperature stable mates through to the more exotic intermetallic materials and on to their reinforcement with ceramics. The use of Ti6/4 alloy is now widespread throughout the aero space industry providing a good combination of strength at moderate temperatures (~300°C) a relatively low density and a wide range of processing options ranging from castings to forgings to powder HIP and diffusion bonding. Alloy development for the aero-engine essentially concentrated on either increasing the temperature capability and creep resistance or increasing the strength at intermediate temperatures. Alloys such as Ti 6242 and IMI 834 were aimed at compressor disc applications with operation up to around 600°C. Improvements resulted from compositional control and thermal processing to optimize the microstructure for creep and fatigue. High strength intermediate temperature capability (~500°C) alloys were also developed (Ti6246) where higher levels of molybdenum balance the alpha strengthening additions. The drive for lighter weight led to the development of titanium intermetallic systems. Alloys such as 45-2-2XD and Alloy 7 have been the subject of much research and manufacturing development over the last 20 years, demonstrating that they are capable of operating at temperatures well above those of conventional titanium. More recently, alloys with higher additions of Nb and Ta have shown improved mechanical properties and offer promise to extend the application of TiAl above 700°C. In parallel with intermetallic developments combining titanium alloys with the extreme high strength of ceramic fibres has proved irresistible and many ways to produce titanium composites have been developed. The majority of application development has focused on Ti6/4 alloy as the matrix although other matrix alloys have been investigated and tested in U.S. engine demonstrators. Recently a combination of Ti-22Al-26Nb disks reinforced with orthorhombic MMC ran for over 100 hours in an engine test. However, none of these niche composite systems has yet made the transition into large volume production and the fibre reinforced Ti6/4 system probably offers the greatest potential for implementation. The main barrier to the take up of both advanced intermetallics and titanium composites is the cost of raw materials and processing. The challenge still exists to produce net shape components and provide weight savings at an acceptable cost. This will be the key to future exploitation.

Addressing the Challenge of Aircraft Component Design and Manufacture from Metal Matrix Composites

1992 ◽  
Vol 206 (1) ◽  
pp. 1-13
Author(s):  
D Charles
Keyword(s):  
Metal Matrix Composites ◽  
Metal Matrix ◽  
High Strength ◽  
Matrix Alloy ◽  
Matrix Composites ◽  
Component Design ◽  
Wide Range ◽  
The Matrix ◽  
Successful Design ◽  
Design And Manufacture

Metal matrix composites (MMCs) offer considerable potential for providing lightweight components exhibiting high strength, high stiffness, good wear resistance and improved elevated temperature performance in comparison to the matrix alloy. Consequently they are applicable to a wide range of aerospace products. The potential offered by this class of materials has resulted in considerable effort being expanded to address the challenges posed by the design*** and manufacture of aerospace components from these materials. These efforts have culminated in the successful design, manufacture and test of representative aircraft components from metal matrix composites.

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