scholarly journals Effect of W Alloying and NbC Dispersion on High Temperature Strength at 1773 K and Room Temperature Fracture Toughness in Nb5Si3/Nb In-situ Composites

2002 ◽  
Vol 43 (6) ◽  
pp. 1415-1418 ◽  
Author(s):  
Won-Yong Kim ◽  
Hisao Tanaka ◽  
Shuji Hanada
Keyword(s):  
Fracture Toughness ◽  
High Temperature ◽  
Room Temperature ◽  
High Temperature Strength ◽  
Temperature Fracture

Effects of Re Alloying on Mechanical Properties of In-Situ Composites with Base Composition of Nb-18Si-2HfC

2006 ◽  
Vol 306-308 ◽  
pp. 941-946
Author(s):  
Sheng Wu Wang ◽  
Tatsuo Tabaru ◽  
Hisatoshi Hirai ◽  
Hideto Ueno
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
High Temperature ◽  
Base Composition ◽  
Room Temperature ◽  
High Temperature Strength ◽  
Strengthening Effect ◽  
In Situ Composites ◽  
Temperature Fracture

Nb-base in-situ composites with the base composition of Nb-18Si-2HfC were prepared by conventional arc-melting. Their microstructures and mechanical properties, such as high-temperature strength and room temperature fracture toughness, were investigated to elucidate the effects of Re alloying. The in-situ composites predominantly have eutectic microstructures consisting of an Nb solid solution (NbSS) and Nb5Si3. The compressive strength increased with the increasing Re contents at 1470K and not at 1670 K. The strengthening effect observed at 1470 K is higher than that by W and Mo. Re alloying of about 2 % is valuable for improving both the high temperature strength and room temperature fracture toughness of Nb-18Si-2HfC base materials.

Room temperature fracture toughness and high temperature strength of T2/Moss and (Mo,Nb)ss/T1/T2 eutectic alloys in the Mo–Si–B system

2003 ◽  
Vol 49 (4) ◽  
pp. 285-290 ◽  
Author(s):  
Kazuhiro Ito ◽  
Michiaki Kumagai ◽  
Taisuke Hayashi ◽  
Masaharu Yamaguchi
Keyword(s):  
Fracture Toughness ◽  
High Temperature ◽  
Room Temperature ◽  
High Temperature Strength ◽  
Eutectic Alloys ◽  
Temperature Fracture

Effect of Rolling Parameters on the Properties of Al-Fe-V Sheet Rolled on an Experimental Mill

1985 ◽  
Vol 58 ◽  
Author(s):  
A. Brown ◽  
D. Raybould
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Aluminum Alloys ◽  
Room Temperature ◽  
Thermomechanical Processing ◽  
High Temperature Strength ◽  
Rapidly Solidified ◽  
Large Sheet ◽  
Room Temperature Strength

ABSTRACTIn recent years, interest in high temperature aluminum alloys has increased. However, nearly all the data available is for simple extrusions. This paper looks at the properties of sheet made from a rapidly solidified Al-10Fe-2.5V-2Si alloy. The sheet is made by direct forging followed by hot rolling, this is readily scalable, so allowing the production of large sheet. The room temperature strength and fracture toughness of the sheet are comparable to those of 2014-T6. The high temperature strength, specific stiffness and corrosion resistance are excellent. Recently, improved thermomechanical processing and new alloys have allowed higher strengths and fracture toughness values to be obtained.

Analyses of Eutectoid Phase Transformations in Nb–SilicideIn SituComposites

2004 ◽  
Vol 10 (4) ◽  
pp. 470-480 ◽  
Author(s):  
B.P. Bewlay ◽  
S.D. Sitzman ◽  
L.N. Brewer ◽  
M.R. Jackson
Keyword(s):  
Crystal Structure ◽  
Phase Transformation ◽  
High Temperature ◽  
Room Temperature ◽  
Bulk Composition ◽  
High Strength ◽  
Eutectoid Decomposition ◽  
Quaternary Alloys ◽  
Temperature Fracture

Nb–silicide in situ composites have great potential for high-temperature turbine applications. Nb–silicide composites consist of a ductile Nb-based solid solution together with high-strength silicides, such as Nb5Si3and Nb3Si. With the appropriate addition of alloying elements, such as Ti, Hf, Cr, and Al, it is possible to achieve a promising balance of room-temperature fracture toughness, high-temperature creep performance, and oxidation resistance. In Nb–silicide composites generated from metal-rich binary Nb-Si alloys, Nb3Si is unstable and experiences eutectoid decomposition to Nb and Nb5Si3. At high Ti concentrations, Nb3Si is stabilized to room temperature, and the eutectoid decomposition is suppressed. However, the effect of both Ti and Hf additions in quaternary alloys has not been investigated previously. The present article describes the discovery of a low-temperature eutectoid phase transformation during which (Nb)3Si decomposes into (Nb) and (Nb)5Si3, where the (Nb)5Si3possesses the hP16 crystal structure, as opposed to the tI32 crystal structure observed in binary Nb5Si3. The Ti and Hf concentrations were adjusted over the ranges of 21 to 33 (at.%) and 7.5 to 33 (at.%) to understand the effect of bulk composition on the phases present and the eutectoid phase transformation.

High temperature compressive properties and room temperature fracture toughness of directionally solidified NiAl-based eutectic alloy

2009 ◽  
Vol 30 (6) ◽  
pp. 2181-2185 ◽  
Author(s):  
Yongchun Liang ◽  
Jianting Guo ◽  
Yi Xie ◽  
Lanzhang Zhou ◽  
Zhuangqi Hu
Keyword(s):  
Fracture Toughness ◽  
High Temperature ◽  
Eutectic Alloy ◽  
Room Temperature ◽  
Directionally Solidified ◽  
Compressive Properties ◽  
Temperature Fracture

Microstructure and room temperature fracture toughness of Nbss/Nb5Si3 in situ composites

2001 ◽  
Vol 9 (9) ◽  
pp. 827-834 ◽  
Author(s):  
Won-Yong Kim ◽  
Hisao Tanaka ◽  
Akio Kasama ◽  
Shuji Hanada
Keyword(s):  
Fracture Toughness ◽  
Room Temperature ◽  
In Situ Composites ◽  
Temperature Fracture

Grain Boundaries and Interfaces in MoSi2 and MoSi2-SiC Composites and Their Effect on High Temperature Strength

2000 ◽  
Vol 6 (S2) ◽  
pp. 424-425
Author(s):  
R. Mitra ◽  
W.-A. Chiou ◽  
A. Venugopal Rao
Keyword(s):  
High Temperature ◽  
Grain Boundaries ◽  
Weight Fraction ◽  
High Temperature Strength ◽  
High Melting Point ◽  
Temperature Oxidation ◽  
Structural Applications ◽  
Temperature Fracture ◽  
Sic Composites

Molybdenum di-silicides (MoSi2) based materials have a strong potential for high temperature structural applications due to high melting point of 2030°C, outstanding elevated temperature oxidation resistance and limited ductility above a temperature range of 1100-1300°C. The major shortcomings of MoSi2 for structural applications are its poor room temperature fracture toughness and low high temperature strength. Sustained efforts including reinforcing MoSi2 with ceramic reinforcements, alloying and in-situ processing, have been made to improve these properties. The purity of grain boundaries and interfaces, which in turn depends on the processing method plays a significant role in the high temperature properties and this paper aims to show that.Intimately mixed Mo and Si powders (Mo:Si = 63:37 by weight fraction) were reaction hot pressed (“RHP“) in vacuum at 1500°C for 1 h, using a pressure of 26 MPa. During the hot pressing process, Mo and Si reacted to form MoSi2.

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