Characterization of the Fracture Toughness of the Concrete Mortars Exposed to Elevated Temperatures

2009 ◽  
Vol 6 (2) ◽  
pp. 296-305
Author(s):  
S. Djaknoun ◽  
A. Ahmed Benyahia ◽  
E. Ouedraogo
2006 ◽  
Vol 321-323 ◽  
pp. 913-916
Author(s):  
Sang Ll Lee ◽  
Yun Seok Shin ◽  
Jin Kyung Lee ◽  
Jong Baek Lee ◽  
Jun Young Park

The microstructure and the mechanical property of liquid phase sintered (LPS) SiC materials with oxide secondary phases have been investigated. The strength variation of LPS-SiC materials exposed at the elevated temperatures has been also examined. LPS-SiC materials were sintered at the different temperatures using two types of Al2O3/Y2O3 compositional ratio. The characterization of LPS-SiC materials was investigated by means of SEM with EDS, three point bending test and indentation test. The LPS-SiC material with a density of about 3.2 Mg/m3 represented a flexural strength of about 800 MPa and a fracture toughness of about 9.0 MPa⋅√m.


Author(s):  
C L Chow ◽  
K Y Sze

The recent emphasis on improving tyre structure integrity against premature failures has led to an increased effort to study fracture behaviour of different carbon black reinforced tyre compounds. Due to the general hysteretic nature of tyre materials, the overall working temperature of a tyre is elevated under service conditions. Relative merits in the characterization of crack initiation in a typical tyre compound using the conventional quasi-static energy and J-integral approaches were first examined. The quasi-static energy method has been applied to evaluate the fracture toughness of materials exhibiting either linear or non-linear elastic behaviour within the confines of the linear elastic energetic approach. Based on the ease of analysis and ability to make multiple measurements on a single specimen, the quasi-static energy approach is chosen to measure the fracture toughness of the tyre material at temperatures of 23, 37, 52, 62 and 73°C. The fracture toughness measured for the tyre material has been observed to be inversely proportional to the temperature elevation. The observation agrees with earlier investigations that the crack growth rate of rubbers under fatigue loading decreased with an increase in temperature in the test materials.


Author(s):  
Gyeung Ho Kim ◽  
Mehmet Sarikaya ◽  
D. L. Milius ◽  
I. A. Aksay

Cermets are designed to optimize the mechanical properties of ceramics (hard and strong component) and metals (ductile and tough component) into one system. However, the processing of such systems is a problem in obtaining fully dense composite without deleterious reaction products. In the lightweight (2.65 g/cc) B4C-Al cermet, many of the processing problems have been circumvented. It is now possible to process fully dense B4C-Al cermet with tailored microstructures and achieve unique combination of mechanical properties (fracture strength of over 600 MPa and fracture toughness of 12 MPa-m1/2). In this paper, microstructure and fractography of B4C-Al cermets, tested under dynamic and static loading conditions, are described.The cermet is prepared by infiltration of Al at 1150°C into partially sintered B4C compact under vacuum to full density. Fracture surface replicas were prepared by using cellulose acetate and thin-film carbon deposition. Samples were observed with a Philips 3000 at 100 kV.


Author(s):  
K.L. More ◽  
R.A. Lowden

The mechanical properties of fiber-reinforced composites are directly related to the nature of the fiber-matrix bond. Fracture toughness is improved when debonding, crack deflection, and fiber pull-out occur which in turn depend on a weak interfacial bond. The interfacial characteristics of fiber-reinforced ceramics can be altered by applying thin coatings to the fibers prior to composite fabrication. In a previous study, Lowden and co-workers coated Nicalon fibers (Nippon Carbon Company) with silicon and carbon prior to chemical vapor infiltration with SiC and determined the influence of interfacial frictional stress on fracture phenomena. They found that the silicon-coated Nicalon fiber-reinforced SiC had low flexure strengths and brittle fracture whereas the composites containing carbon coated fibers exhibited improved strength and fracture toughness. In this study, coatings of boron or BN were applied to Nicalon fibers via chemical vapor deposition (CVD) and the fibers were subsequently incorporated in a SiC matrix. The fiber-matrix interfaces were characterized using transmission and scanning electron microscopy (TEM and SEM). Mechanical properties were determined and compared to those obtained for uncoated Nicalon fiber-reinforced SiC.


Alloy Digest ◽  
1994 ◽  
Vol 43 (11) ◽  

Abstract CARLSON ALLOYS C600 AND C600 ESR have excellent mechanical properties from sub-zero to elevated temperatures with excellent resistance to oxidation at high temperatures. It is a solid-solution alloy that can be hardened only by cold working. High strength at temperature is combined with good workability. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, and machining. Filing Code: Ni-470. Producer or source: G.O. Carlson Inc.


Alloy Digest ◽  
1976 ◽  
Vol 25 (12) ◽  

Abstract FEDERAL BRONZE 822 is a copper-base, high-lead bearing bronze with superior resistance to scoring and seizure beyond the endurance and danger limits of ordinary bearing bronzes. It is used in applications involving high speeds, poor lubrication, heat-generating loads, elevated temperatures, dusty and gritty surroundings, or where a liquid other than oil is used as the lubricant. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive strength as well as fracture toughness. It also includes information on casting, heat treating, machining, joining, and surface treatment. Filing Code: Cu-324. Producer or source: Federal Bronze Products Inc..


Alloy Digest ◽  
1974 ◽  
Vol 23 (12) ◽  

Abstract FEDERATED F401.5Ni is a heat-treatable aluminum casting alloy with high strength and good wear resistance in the fully heat-treated condition. It is recommended for castings requiring good strength at elevated temperatures. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Al-212. Producer or source: Federated Metals Corporation, ASARCO Inc..


Alloy Digest ◽  
2009 ◽  
Vol 58 (3) ◽  

Abstract Inconel Alloy N06230 is a Ni-Cr-W alloy with excellent strength and resistance to oxidation at elevated temperatures. This alloy offers good metallurgical stability and is readily fabricated by conventional processes and procedures. This datasheet provides information on composition, physical properties, microstructure, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ni-667. Producer or source: Special Metals Corporation.


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