A Perspective on MoSi2 Based Composites

1992 ◽  
Vol 273 ◽  
Author(s):  
J. J. Petrovic ◽  
A. K. Vasudevan

ABSTRACTMoSi2 based composites represent an important new class of “high temperature structural silicides”, with significant potential for elevated temperature structural applications in the range of 1200–1600 °C in oxidizing and aggressive environments. The properties of MoSi2 which make it an attractive matrix for high temperature composites are described and the developmental history of these materials traced. Latest results on elevated temperature creep resistance, low temperature fracture toughness, and composite oxidation behavior are summarized. Important avenues for future MoSi2 based composite development are suggested.

1994 ◽  
Vol 344 ◽  
Author(s):  
Geoffrey R. Morrison ◽  
Nolan K. Lee ◽  
Simon A.M. Hesp

AbstractThis paper discusses some important issues related to the use of recycled thermoplastics and rubber tire waste in asphalt binders for hot-mix pavements. Both high temperature rheological and low temperature fracture studies are presented on recycled polyethylene, devulcanized and crumb rubber-modified asphalt binders. The results are compared to unmodified and commercially available modified binders. This research is especially timely in light of the U.S. Intermodal Surface Transportation Efficiency Act of 1991, Section 1038 which, starting in 1995, will force state and local governments to use significant amounts of recycled rubber tire or plastic waste in federally funded highway projects.High temperature rheological measurements of the loss modulus, loss tangent and complex modulus show a significant improvement when only small quantities of crumb rubber, devulcanized crumb rubber or waste polyethylene are added to the asphalt binders.The low temperature fracture performance of the modified asphalts is greatly influenced by the interfacial strength between the dispersed and continuous phase. The fracture toughness increases dramatically, only when low molecular weight polymers are grafted in-situ onto the rubber and polymer dispersed phases in order to strengthen the interface. This points to a crack-pinning mechanism as being responsible for the dramatic increase in fracture toughness that is observed in this work. Single phase, devulcanized crumb rubber-asphalt systems perform quite poorly at low temperatures.


Alloy Digest ◽  
1970 ◽  
Vol 19 (12) ◽  

Abstract WC Ta-10W is a tantalum-base alloy having a combination of low-temperature ductility and fabricability in both the recrystalilzed and wrought conditions, as well as excellent weld ductility. Developed originally for structural applications at elevated temperatures, it is now available in a complete line of aerospace hardware. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness and creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ta-1. Producer or source: Teledyne Wah Chang Albany.


Alloy Digest ◽  
1987 ◽  
Vol 36 (12) ◽  

Abstract UHB QRO 80 MICRODIZED is a chromium-molybdenum-vanadium tool steel with improved performance for tooling used at elevated temperature as in forging, extrusion and die casting. It is electro-slag refined. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance as well as forming, heat treating, machining, and joining. Filing Code: TS-486. Producer or source: Uddeholm Aktiebolag.


Alloy Digest ◽  
1973 ◽  
Vol 22 (12) ◽  

Abstract TIN is used as a coating on steel and on other metals and alloys. When alloyed with other metals, it is an important constituent in soft solders, collapsible tubes, pewter ware, costume jewelry, fusable pressure plugs, bronze and bearing linings. It has a long and varied history of commercial and ornamental uses. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness and creep. It also includes information on low and high temperature performance, and corrosion resistance as well as casting, forming, heat treating, machining, and joining. Filing Code: Sn-5. Producer or source: World tin producers (ingots).


Alloy Digest ◽  
1960 ◽  
Vol 9 (3) ◽  

Abstract NICLOY 5 is a low carbon, nickel ferritic steel reecommended for low temperature service. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on low and high temperature performance, and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SA-96. Producer or source: Babcock & Wilcox Company.


2014 ◽  
Vol 33 (3) ◽  
pp. 193-200 ◽  
Author(s):  
Jiteng Wang ◽  
Juan Wang ◽  
Yajiang Li ◽  
Deshuang Zheng

AbstractMolybdenum and molybdenum alloys are considered to be attractive structural materials for high-temperature applications. However, molybdenum alloys are sensitive to gas impurities and have the characteristics of low temperature embrittlement and less resistance to oxidation at elevated temperature. The toughness and strength of welded joint is not easy to be ensured by traditional technology. Recently, many efforts have been made to join molybdenum and its alloys. In this paper, we present the result of investigations on welding methods of molybdenum and its alloys and overview the practical applications in engineering. The key of joining molybdenum alloys is to improve the toughness of welded joint and prevent the generation of pores and cracks.


1997 ◽  
Vol 16 (2) ◽  
pp. 149-157 ◽  
Author(s):  
G. Gupta, ◽  
S. Wadekar, ◽  
J.S. Dubey, ◽  
R.T. Savalia, ◽  
K.S. Balakrishnan, ◽  
...  

1994 ◽  
Vol 350 ◽  
Author(s):  
M. G. Hebsur

AbstractThe objective of this investigation was to identify a pest resistant MoSi2-base matrix composition having properties suitable for SiC reinforcement. A 30 vol.% addition of fine Si3N4 particulates to MoSi2 significantly improved the low temperature accelerated oxidation resistance and thereby eliminated pest failure. Addition of Si3N4 also improved the high temperature oxidation resistance, strength and more importantly lowered the CTE of MoSi2 such that cracking was eliminated in a hybrid composite consisting of 30 vol.% Si3N4 and 30 vol. % SCS-6 fibers.


2010 ◽  
Vol 1252 ◽  
Author(s):  
Sahar Sahhaf ◽  
Robin Degraeve ◽  
Mohammed Zahid ◽  
Guido Groeseneken

AbstractIn this work, the effect of elevated temperature on the generated defects with constant voltage stress (CVS) in SiO2 and SiO2/HfSiO stacks is investigated. Applying Trap Spectroscopy by Charge Injection and Sensing (TSCIS) to 6.5 nm SiO2 layers, different kinds of generated traps are profiled at low and high temperature. Also the Stress-Induced Leakage Current (SILC) spectrum of high-k dielectric stack is different at elevated temperature indicating that degradation and breakdown at high temperature is not equivalent to that at low temperature and therefore, extrapolation of data from high to low T or vice versa is challenging.


Sign in / Sign up

Export Citation Format

Share Document