scholarly journals Oxidation Resistance of Nanocrystalline Alloys

10.5772/34928 ◽  
2012 ◽  
Author(s):  
Nick Birbilis ◽  
Jianqiang Zhang ◽  
Rajeev Gupt
2011 ◽  
Vol 171 ◽  
pp. 51-66 ◽  
Author(s):  
S.K. Sharma

Amorphous alloys, in general, exhibit superior mechanical and chemical properties as compared to their crystalline counterparts, which is attributed to their chemical homogeneity and to the absence of crystal-like structural defects. Nanocrystalline and fully crystallized forms of these alloys can be easily obtained by a suitable thermal annealing treatment. It is important to have the knowledge of corrosion/oxidation behavior of amorphous and nanocrystalline alloys for various possible applications. In contrast to many investigations on corrosion and oxidation behavior of amorphous alloys reported in the literature, only limited studies have been carried out on comparison of corrosion/oxidation behavior of amorphous and nanocrystalline states of the same alloy. With this motivation potentiodynamic polarization studies were carried out on amorphous and nanocrystalline states of the alloy Ti60Ni40 in several aqueous media at room temperature. The oxidation in air was also investigated in the temperature range 2800C-3800C using a thermogravimetric analyzer. It was found from these investigations that nanocrystalline state exhibits the maximum corrosion/oxidation resistance in comparison to amorphous and crystalline states. The better corrosion/oxidation resistance of nanocrystalline state can be explained in terms of the nature of the nanocrystalline phase/phases and the size of the crystallites. The results of the present study are supported by other similar studies reported in the literature. A short review on comparison of corrosion/oxidation behaviour of amorphous and nanocrystalline Ti-based alloy is also presented in the paper.


Author(s):  
C. S. Giggins ◽  
J. K. Tien ◽  
B. H. Kear ◽  
F. S. Pettit

The performance of most oxidation resistant alloys and coatings is markedly improved if the oxide scale strongly adheres to the substrate surface. Consequently, in order to develop alloys and coatings with improved oxidation resistance, it has become necessary to determine the conditions that lead to spallation of oxides from the surfaces of alloys. In what follows, the morphological features of nonadherent Al2O3, and the substrate surfaces from which the Al2O3 has spalled, are presented and related to oxide spallation.The Al2O3, scales were developed by oxidizing Fe-25Cr-4Al (w/o) and Ni-rich Ni3 (Al,Ta) alloys in air at 1200°C. These scales spalled from their substrates upon cooling as a result of thermally induced stresses. The scales and the alloy substrate surfaces were then examined by scanning and replication electron microscopy.The Al2O3, scales from the Fe-Cr-Al contained filamentary protrusions at the oxide-gas interface, Fig. 1(a). In addition, nodules of oxide have been developed such that cavities were formed between the oxide and the substrate, Fig. 1(a).


Author(s):  
H. Kung ◽  
T. R. Jervis ◽  
J.-P. Hirvonen ◽  
M. Nastasi ◽  
T. E. Mitchell ◽  
...  

MoSi2 is a potential matrix material for high temperature structural composites due to its high melting temperature and good oxidation resistance at elevated temperatures. The two major drawbacksfor structural applications are inadequate high temperature strength and poor low temperature ductility. The search for appropriate composite additions has been the focus of extensive investigations in recent years. The addition of SiC in a nanolayered configuration was shown to exhibit superior oxidation resistance and significant hardness increase through annealing at 500°C. One potential application of MoSi2- SiC multilayers is for high temperature coatings, where structural stability ofthe layering is of major concern. In this study, we have systematically investigated both the evolution of phases and the stability of layers by varying the heat treating conditions.Alternating layers of MoSi2 and SiC were synthesized by DC-magnetron and rf-diode sputtering respectively. Cross-sectional transmission electron microscopy (XTEM) was used to examine three distinct reactions in the specimens when exposed to different annealing conditions: crystallization and phase transformation of MoSi2, crystallization of SiC, and spheroidization of the layer structures.


Alloy Digest ◽  
2004 ◽  
Vol 53 (12) ◽  

Abstract Udimet L-605 is a high-temperature aerospace alloy with excellent strength and oxidation resistance. It is used in applications such as gas turbine blades and combustion area parts. This datasheet provides information on composition, physical properties, and tensile properties as well as creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, and joining. Filing Code: CO-109. Producer or source: Special Metals Corporation.


Alloy Digest ◽  
2013 ◽  
Vol 62 (4) ◽  

Abstract NAS HX (UNS N06002) is a nickel-chromium-iron-molybdenum alloy with outstanding strength and oxidation resistance. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance as well as forming, heat treating, and joining. Filing Code: Ni-707. Producer or source: Nippon Yakin Kogyo Company Ltd.


Alloy Digest ◽  
1967 ◽  
Vol 16 (1) ◽  

Abstract RA-600 is a nickel-base chromium alloy having good oxidation resistance to 2150 F, and good resistance to carburizing and nitriding atmospheres. It is recommended for furnace construction and equipment. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as creep. It also includes information on corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Ni-120. Producer or source: Rolled Alloys Inc..


Alloy Digest ◽  
2005 ◽  
Vol 54 (11) ◽  

Abstract Incotherm TD is a thermocouple-sheathing alloy with elements of silicon and rare earths to enhance oxidation resistance at high temperatures. This datasheet provides information on composition, physical properties, and tensile properties as well as deformation. It also includes information on high temperature performance and corrosion resistance as well as forming. Filing Code: Ni-628. Producer or source: Special Metals Corporation.


Alloy Digest ◽  
1958 ◽  
Vol 7 (3) ◽  

Abstract INCONEL 702 is a nickel-base alloy having moderate strength with exceptional oxidation resistance at elevated temperatures. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ni-40. Producer or source: International Nickel Company Inc..


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