Microstructural characterization of a Cr2Nb-Nb(Cr) microlaminate composite

1994 ◽  
Vol 52 ◽  
pp. 706-707
Author(s):  
M. Larsen ◽  
R. G. Rowe ◽  
D. W. Skelly
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Metal Layer ◽  
Intermetallic Layer ◽  
Weight Ratio ◽  
Microstructural Characterization ◽  
Aircraft Engine ◽  
Intrinsic Defect ◽  
Lamellar Thickness

The thrust to weight ratio of an aircraft engine is limited by the density and elevated temperature performance of high temperature structural materials. Many material systems are currently under investigation as potential next generation engine materials. Microlaminate composites consisting of alternating layers of a ductile refractory metal for toughening and a high temperature intermetallic compound for elevated temperature strength have applicability in aircraft engine turbines. The lamellar thickness of such a composite must be small because the intrinsic defect size, a crack across the intermetallic layer, will be controlled by the intermetallic layer thickness. The microstructural characterization of a Cr2Nb-Nb(Cr) microlaminate composite produced by Magnetron® sputtering was carried out by cross-sectional TEM. Both the as-deposited composite and one heat treated at 1200°C for two hours were examined.Figure 1 shows a micrograph of the as-deposited composite. The metal and intermetallic layers are 2um thick. The metal layer has a composition in atomic percent of 95% Nb and 5% Cr.

Microstructural characterization of a rapidly solidified Al-Fe-V-Si alloy for elevated temperature applications

1988 ◽  
Vol 46 ◽  
pp. 550-551
Author(s):  
R. E. Franck ◽  
J. A. Hawk ◽  
G. J. Shiflet
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Grain Growth ◽  
Volume Fraction ◽  
Microstructural Characterization ◽  
Second Phase ◽  
Microstructural Stability ◽  
Elevated Temperature Strength ◽  
Temperature Applications

Rapid solidification processing (RSP) is one method of producing high strength aluminum alloys for elevated temperature applications. Allied-Signal, Inc. has produced an Al-12.4 Fe-1.2 V-2.3 Si (composition in wt pct) alloy which possesses good microstructural stability up to 425°C. This alloy contains a high volume fraction (37 v/o) of fine nearly spherical, α-Al12(Fe, V)3Si dispersoids. The improved elevated temperature strength and stability of this alloy is due to the slower dispersoid coarsening rate of the silicide particles. Additionally, the high v/o of second phase particles should inhibit recrystallization and grain growth, and thus reduce any loss in strength due to long term, high temperature annealing.The focus of this research is to investigate microstructural changes induced by long term, high temperature static annealing heat-treatments. Annealing treatments for up to 1000 hours were carried out on this alloy at 500°C, 550°C and 600°C. Particle coarsening and/or recrystallization and grain growth would be accelerated in these temperature regimes.

Microstructural characterization of alloyed palladium coated copper wire under high temperature

2021 ◽  
Vol 120 ◽  
pp. 114125
Author(s):  
Motoki Eto ◽  
Noritoshi Araki ◽  
Takashi Yamada ◽  
Masaaki Sugiyama ◽  
Shinji Fujimoto
Keyword(s):  
High Temperature ◽  
Copper Wire ◽  
Microstructural Characterization

Microstructural Characterization of α2 + γ Titanium Aluminides

1997 ◽  
Vol 3 (S2) ◽  
pp. 701-702
Author(s):  
D. J. Larson ◽  
M. K. Miller
Keyword(s):  
Titanium Aluminides ◽  
Base Alloy ◽  
Significant Proportion ◽  
Weight Ratio ◽  
High Strength ◽  
Microstructural Characterization ◽  
Two Phase ◽  
Tial Alloys ◽  
Boron Doped

Two-phase α2+γ TiAl alloys with microalloying additions, Fig. 1, are of interest due to the high strength-to-weight ratio they can provide in automotive and aircraft applications. In boron-doped α2+γTiAl containing Cr, Nb, and W, the B levels were found to be significantly depleted below the nominal alloy content in both the α2 andγ phases. The boron solubilities in the γ and α2 phases were 0.011 ± 0.005 at. % B and 0.003 ± 0.005 at. % B, respectively in Ti-47% Al-2% Cr-1.8% Nb-0.2% W-0.15 % B that was aged for 2 h at 900°C (base alloy). The majority of the B was in a variety of borides including TiB, TiB2 and a Cr-enriched (Ti,Cr)2B precipitate. With the exception of the smaller (< 50 nm thick) Cr-enriched (Ti,Cr)2B precipitates, Fig. 2, most of the borides were larger than ∼100 nm. A significant proportion of the microalloying additions is in these borides, Table 1.

Characterization of Ti/TiN and TiN Conductive Layer for High Temperature MEMS Devices

2005 ◽  
Vol 872 ◽  
Author(s):  
Peter Lange ◽  
Birger Ohlsen ◽  
Sebastian Puls ◽  
Joerg Syre
Keyword(s):  
Thermal Stability ◽  
High Temperature ◽  
Elevated Temperature ◽  
Mechanical Stability ◽  
Fast Response ◽  
Conductive Layer ◽  
Mems Devices ◽  
Thermal Isolation ◽  
Effects Of Temperature

AbstractThe effects of temperature on micro heaters made of Ti/TiN stacks and pure TiN layers on bulk micromachined membranes have been studied. Ti/TiN stacks show a thermal stability up to 380°C, beyond that temperature an enhanced interaction within the stack and/or with adjacend layers leads to a degradation of the resistance. The pure TiN layers withstand temperatures up to 600 °C, this limitation is only given by the mechanical stability of the membran stack, which is destroyed beyond this temperature. These layers are suitable for sensors in which an elevated temperature provided by heating lines on a membran for thermal isolation and fast response is necessary for functionality.

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