scholarly journals Microstructure and mechanical properties of melt-grown alumina-mullite/glass composites fabricated by directed laser deposition

2021 ◽  
Author(s):  
Dake Zhao ◽  
Dongjiang Wu ◽  
Jing Shi ◽  
Fangyong Niu ◽  
Guangyi Ma
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
Laser Deposition ◽  
Columnar Dendrite ◽  
Rapid Preparation ◽  
Constitutional Undercooling ◽  
Glass Composites ◽  
Aerospace Applications ◽  
Key Issues ◽  
Glass Interface

AbstractMelt-grown alumina-based composites are receiving increasing attention due to their potential for aerospace applications; however, the rapid preparation of high-performance components remains a challenge. Herein, a novel route for 3D printing dense (< 99.4%) high-performance melt-grown alumina-mullite/glass composites using directed laser deposition (DLD) is proposed. Key issues on the composites, including phase composition, microstructure formation/evolution, densification, and mechanical properties, are systematically investigated. The toughening and strengthening mechanisms are analyzed using classical fracture mechanics, Griffith strength theory, and solid/glass interface infiltration theory. It is demonstrated that the composites are composed of corundum, mullite, and glass, or corundum and glass. With the increase of alumina content in the initial powder, corundum grains gradually evolve from near-equiaxed dendrite to columnar dendrite and cellular structures due to the weakening of constitutional undercooling and small nucleation undercooling. The microhardness and fracture toughness are the highest at 92.5 mol% alumina, with 18.39±0.38 GPa and 3.07±0.13 MPa·m1/2, respectively. The maximum strength is 310.1±36.5 MPa at 95 mol% alumina. Strength enhancement is attributed to the improved densification due to the trace silica doping and the relief of residual stresses. The method unravels the potential of preparing dense high-performance melt-grown alumina-based composites by the DLD technology.

Studying Mechanical Properties Specially Fatigue Behavior of (Polyether Ether Ketone)/Glass Fiber Composites in Aerospace Applications

2014 ◽  
Vol 666 ◽  
pp. 8-16
Author(s):  
A. Saad Najim ◽  
Mohammed Adwaa
Keyword(s):  
Mechanical Properties ◽  
Glass Fiber ◽  
High Performance ◽  
Fatigue Behavior ◽  
Fatigue Properties ◽  
Glass Fiber Composites ◽  
Aerospace Applications ◽  
Polyether Ether Ketone ◽  
High Performance Composite ◽  
Ether Ketone

This work deals with studying the mechanical properties specially fatigue behavior for high performance composite materials of poly ether ether ketone (PEEK)/glass fiber, which are used in Aircraft Industry. Two materials have been used: (PEEK natural) and (PEEK+30% glass fiber).To identify the type of (PEEK), infrared (FTIR) test has been conducted. X-ray test has been used to measure the (PEEK) crystalline ,also the tensile properties, impact strength and the fatigue test are performed.The results show that FTIR test peaks are for standard PEEK polymer and that GFRP increases the crystalline of (PEEK) material , while the tensile , impact and fatigue properties of (PEEK) decreases by adding GF to PEEK .

Preliminary adhesive and composite properties of LARC™-CPI 2, a new semicrystalline polyimide

1993 ◽  
Vol 5 (3) ◽  
pp. 177-185 ◽  
Author(s):  
P M Hergenrothert ◽  
S J Havens
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Glass Transition ◽  
Transition Temperature ◽  
High Performance ◽  
Melt Temperature ◽  
High Molecular Weight Form ◽  
Aerospace Applications ◽  
Composite Properties ◽  
Molecular Weight Form

In continuation of an effort to develop processable high-performance structural resins for use in aerospace applications, a new polyimide. LARCTM-CPI 2, has been developed. This semicrystalline polyimide was prepared by the reaction of 4.4'-oxydiphthalic anhydride with 1,4-bis(4-aminophenoxy-4'-benzoyl)benzene. In high-molecular-weight form this material has a glass transition temperature of 223 C and a crystalline melt temperature of approximately 350 'C. Controlled-molecular-weight end-capped versions of LARCTM-CPI 2 were used to fabricate adhesive panels and composites that exhibited good mechanical properties at temperatures as high as 200 C.

Investigation of Carbon Fibre Reinforced Composites Based on Novel Phenylethynyl-Terminated Polyimde

2011 ◽  
Vol 415-417 ◽  
pp. 310-315
Author(s):  
Cheng Xia Tong ◽  
Guo Dong Dang ◽  
Chun Hai Chen ◽  
Hong Wei Zhou
Keyword(s):  
Mechanical Properties ◽  
Carbon Fibre ◽  
High Performance ◽  
Room Temperature ◽  
Aerospace Applications ◽  
Aging Test ◽  
Before And After ◽  
High Performance Composite ◽  
Polyimide Composites ◽  
Polyimide Matrix

As part of the continuing studies to develop high performance composite based on new kind of phenylethynyl end-capped imide oligomers for aerospace applications, PETI-type polyimide composites were prepared from carbon fibre (CF) and polyimide matrix resin derived from dianhydride (s-BPDA), 2,5-bis(4-aminophenoxy)-biphenyl(p-TPEQ) and 4-phenylethynylphthalic anhydride (PEPA). The mechanical properties were tested at both room temperature and 177 °C. The flexural properties were determined by 3-point-bending at room temperature. Thermal aging test was carried out by exposing samples at 177°C over 1000 hours, and the mechanical properties were also evaluated before and after isothermal aging. It was demonstrated that the composite had good thermal and mechanical properties.

scholarly journals Cooperative Effect of Li Content and Equal-Channel Angular Pressing on Microstructure and Mechanical Properties of Al-Mg-Li Alloy

Metals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 840
Author(s):  
Ting Yuan ◽  
Jinghua Jiang ◽  
Yuna Wu ◽  
Zhipeng Yuan ◽  
Aibin Ma ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Equal Channel Angular Pressing ◽  
High Performance ◽  
Cast Alloy ◽  
Cooperative Effects ◽  
Specific Strength ◽  
Aerospace Applications ◽  
Angular Pressing ◽  
Al Matrix Composites ◽  
Li Content

This paper investigated the cooperative effects of Li addition and warm Equal Channel Angular Pressing (ECAP) on improving the mechanical properties of an Al-Mg-Li alloy for further weight reduction. The results showed that more Li addition could obviously refine the grains of the as-cast alloy and reduce its density value to only 2.37 g/cm3 when Li content reached 2.5% (about 12.6% lighter than commercial Al alloys). It also had a pronounced influence on the precipitations in the Al-5.5Mg-xLi-0.1Zr alloy, i.e., the number density and size of Al2MgLi and δ’-Al3Li phases. The yield strength of the as-cast alloy was increased with increasing Li, but the elongation deteriorated due to primary network intergranular Al2MgLi and more δ’ particles in the high Li-containing alloy. The warm multi-pass ECAP process was found to simultaneously improve the strength and ductility of the Al-Mg-Li alloys, and greatly alleviate the detrimental effect of Li addition on the elongation, thereby making the ultrafine-grained (UFG) alloys, a good combination of lightweight and high performance, very attractive for aerospace applications for much higher specific strength than both Al matrix composites and Mg alloys.

Macroprobe Mode for the Study of Segregation in Steels

1990 ◽  
Vol 48 (2) ◽  
pp. 260-261
Author(s):  
Auclair Gilles ◽  
Benoit Danièle
Keyword(s):  
Mechanical Properties ◽  
Spatial Distribution ◽  
High Performance ◽  
Volume Fraction ◽  
Sheet Steel ◽  
Acquisition Time ◽  
Chemical Information ◽  
X Ray ◽  
Accurate Quantitative Analysis ◽  
Optical Micrographs

During these last 10 years, high performance correction procedures have been developed for classical EPMA, and it is nowadays possible to obtain accurate quantitative analysis even for soft X-ray radiations. It is also possible to perform EPMA by adapting this accurate quantitative procedures to unusual applications such as the measurement of the segregation on wide areas in as-cast and sheet steel products.The main objection for analysis of segregation in steel by means of a line-scan mode is that it requires a very heavy sampling plan to make sure that the most significant points are analyzed. Moreover only local chemical information is obtained whereas mechanical properties are also dependant on the volume fraction and the spatial distribution of highly segregated zones. For these reasons we have chosen to systematically acquire X-ray calibrated mappings which give pictures similar to optical micrographs. Although mapping requires lengthy acquisition time there is a corresponding increase in the information given by image anlysis.

Mechanical properties and durability of high - performance concrete for bridge decks

PCI Journal ◽  
2008 ◽  
Vol 53 (4) ◽  
pp. 108-130
Author(s):  
Mohsen A. Issa ◽  
Atef A. Khalil ◽  
Shahidul Islam ◽  
Paul D. Krauss
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
High Performance Concrete ◽  
Bridge Decks

BERYLCO 25S

Alloy Digest ◽  
1952 ◽  
Vol 1 (3) ◽  
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
Precipitation Hardening ◽  
Elevated Temperatures ◽  
Heat Treating ◽  
Good Resistance ◽  
Subzero Temperatures ◽  
Endurance Strength ◽  
Wear And Corrosion ◽  
Resistance To Wear

Abstract Berylco 25S alloy is the high-performance beryllium-copper spring material of 2 percent nominal beryllium content. It responds to precipitation-hardening for maximum mechanical properties. It has high elastic and endurance strength, good electrical and thermal conductivity, excellent resistance to wear and corrosion, high corrosion-fatigue strength, good resistance to moderately elevated temperatures, and no embrittlement or loss of normal ductility at subzero temperatures. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Cu-3. Producer or source: Beryllium Corporation.

EFFECT OF ZINC DITHIOCARBAMATES AND THIAZOLE-BASED ACCELERATORS ON THE VULCANIZATION OF NATURAL RUBBER

2012 ◽  
Vol 85 (1) ◽  
pp. 120-131 ◽  
Author(s):  
Md. Najib Alam ◽  
Swapan Kumar Mandal ◽  
Subhas Chandra Debnath
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Reaction Mechanism ◽  
Natural Rubber ◽  
High Performance ◽  
Binary Systems ◽  
Synergistic Activity ◽  
Tetramethylthiuram Disulfide

Abstract Several zinc dithiocarbamates (ZDCs) as accelerator derived from safe amine has been exclusively studied in the presence of thiazole-based accelerators to introduce safe dithiocarbamate in the vulcanization of natural rubber. Comparison has been made between conventional unsafe zinc dimethyldithiocarbamate (ZDMC) with safe novel ZDC combined with thizole-based accelerators in the light of mechanical properties. The study reveals that thiuram disulfide and 2-mercaptobenzothiazole (MBT) are always formed from the reaction either between ZDC and dibenzothiazyledisulfide (MBTS) or between ZDC and N-cyclohexyl-2-benzothiazole sulfenamide (CBS). It has been conclusively proved that MBT generated from MBTS or CBS reacts with ZDC and produces tetramethylthiuram disulfide. The observed synergistic activity has been discussed based on the cure and physical data and explained through the results based on high-performance liquid chromatography and a reaction mechanism. Synergistic activity is observed in all binary systems studied. The highest tensile strength is observed in the zinc (N-benzyl piperazino) dithiocarbamate-accelerated system at 3:6 mM ratios. In respect of tensile strength and modulus value, unsafe ZDMC can be successfully replaced by safe ZDCs in combination with thiazole group containing accelerator.

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