Development of Tough and Strong Cubic Titanium Trialuminides

2000 ◽  
Vol 646 ◽  
Author(s):  
Robert A. Varin ◽  
Les Zbroniec ◽  
Zhi Gang Wang
Keyword(s):  
Fracture Toughness ◽  
Fracture Behavior ◽  
Room Temperature ◽  
Fold Increase ◽  
Strength Increase ◽  
Solid Solution Strengthening ◽  
Boron Doped ◽  
Temperature Fracture ◽  
Solution Strengthening ◽  
B Doping

ABSTRACTIn this work, the recent breakthroughs in the understanding of the fracture behavior and fracture toughness of L12-ordered titanium trialuminides are described and discussed. First, it is shown that, as opposed to many other intermetallics and specifically those with an L12 crystal structure, the fracture toughness of L12 titanium trialuminides is insensitive to testing in various environments such as air, water, argon, oxygen and vacuum (∼1.3×10–5 Pa). Second, it is reported here that by increasing the concentration of Ti combined with boron (B) doping, the room temperature fracture toughness of a Mn-stabilized titanium trialuminide can be improved by 100% from ∼4 MPam1/2 to ∼8 MPam1/2 and by 150–250% at 1000°C to ∼(10–12) MPam1/2 with a simultaneous suppression of intergranular fracture (IGF) to ∼(40–50%). Almost three fold increase in yield strength to ∼550 MPa is attained at room temperature for high Ti, boron-doped trialuminides. Both Vickers microhardness and strength increase linearly with increasing concentration of (Ti+B) indicating a classical solid solution strengthening response.

scholarly journals Effect of Microstructural Continuity on Room-Temperature Fracture Toughness of ZrC-Added Mo–Si–B Alloys

2018 ◽  
Vol 59 (4) ◽  
pp. 518-527 ◽  
Author(s):  
Shunichi Nakayama ◽  
Nobuaki Sekido ◽  
Sojiro Uemura ◽  
Sadahiro Tsurekawa ◽  
Kyosuke Yoshimi
Keyword(s):  
Fracture Toughness ◽  
Room Temperature ◽  
Temperature Fracture

The Room Temperature and Elevated Temperature Fracture Toughness Response of Alloy A-286

1978 ◽  
Vol 100 (2) ◽  
pp. 195-199 ◽  
Author(s):  
W. J. Mills
Keyword(s):  
Fracture Toughness ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Second Phase ◽  
Surface Micromorphology ◽  
Second Phase Particles ◽  
The Matrix ◽  
Temperature Fracture ◽  
Increasing Temperature ◽  
Base Superalloy

The elastic-plastic fracture toughness (JIc) response of precipitation strengthened Alloy A-286 has been evaluated by the multi-specimen R-curve technique at room temperature, 700 K (800°F) and 811 K (1000°F). The fracture toughness of this iron-base superalloy was found to decrease with increasing temperature. This phenomenon was attributed to a reduction in the materials’s strength and ductility at elevated temperatures. Electron fractographic examination revealed that the overall fracture surface micromorphology, a duplex dimple structure coupled with stringer troughs, was independent of test temperature. In addition, the fracture resistance of Alloy A-286 was found to be weakened by the presence of a nonuniform distribution of second phase particles throughout the matrix.

Temperature Dependence of Fracture Toughness of the Cubic (L12) Titanium Trialuminides

1996 ◽  
Vol 460 ◽  
Author(s):  
R. A. Varin ◽  
L. Zbroniec
Keyword(s):  
Fracture Toughness ◽  
Stress Intensity Factor ◽  
Room Temperature ◽  
Maximum Load ◽  
Gradual Transition ◽  
Transgranular Cleavage ◽  
Temperature Range ◽  
Temperature Fracture ◽  
Increasing Temperature ◽  
Work Of Fracture

ABSTRACTFracture toughness vs. temperature of the cubic (L12), Mn- modified titanium trialuminide (based on Al3Ti) was investigated in air at the temperature range up to 1000°C. Toughness calculated from the maximum load exhibits a broad peak (KQ≈7–10 MPara0,5) at the 200- 500°C temperature range and then decreases with increasing temperature, reaching a room temperature value of ∼4.5 MPam0.5 at 1000°C. However, the work of fracture (γWOF, J/m2) and the stress intensity factor calculated from it (KIWOF) increases continuously with increasing temperature. Fracture modes exhibit a gradual transition from transgranular cleavage at room temperature to predominantly intergranular failure at the 800- 1000°C range.

Solidification Processing and Fracture Behavior of RuAl-Based Alloys

2004 ◽  
Vol 842 ◽  
Author(s):  
Todd Reynolds ◽  
David Johnson
Keyword(s):  
Solid Solution ◽  
Fracture Toughness ◽  
Fracture Behavior ◽  
Room Temperature ◽  
Volume Fraction ◽  
Solidification Processing ◽  
Ductile Phase

ABSTRACTAlloys of RuAl-Ru were processed using various solidification methods, and the fracture behavior was examined. The fracture toughness values for RuAl-hcp(Ru, Mo) and RuAl-hcp(Ru, Cr) alloys ranged from 23 to 38 MPa√m, while the volume fraction of RuAl ranged from 22 to 56 percent. Increasing the volume fraction of RuAl resulted in a decrease in fracture toughness. The hcp solid solution was shown to be the more ductile phase with a fracture toughness approaching 68 MPa?m, while the B2 solid solution (RuAl) was found to have a fracture toughness less than 13 MPa√m. An alloy of Ru-7Al-38Cr (at.%) that consisted of a hcp matrix with RuAl precipitates had the highest room temperature toughness and the greatest hardness.

The Influence of Secondary Phase on Impact Toughness of Alloyed Iron Aluminides

2020 ◽  
Vol 405 ◽  
pp. 145-150
Author(s):  
Martin Švec ◽  
Adam Hotař ◽  
Věra Vodičková ◽  
Vojtěch Keller
Keyword(s):  
Impact Toughness ◽  
Room Temperature ◽  
Volume Fraction ◽  
Fracture Behaviour ◽  
Secondary Phase ◽  
Iron Aluminides ◽  
The Other ◽  
Secondary Phases ◽  
Solid Solution Strengthening ◽  
Solution Strengthening

The microstructure and fracture surfaces were investigated for five Fe3Al – based iron aluminides doped by different alloying elements (Nb, Zr + C, Cr) or without addition. Generally, iron aluminides are considered as brittle material at room temperature, therefore the type and distribution of secondary phases affect the fracture behaviour. The influence of present secondary phase particles on impact toughness at room temperature was evaluated in comparison to binary alloy. The type and the volume fraction of particles affect the value of impact toughness significantly – these values decrease with increasing volume fraction of precipitates. On the other hand, the solid solution strengthening improves impact toughness.

Alloy Modeling and Experimental Correlation for Ductility Enhancement in NiAl

1988 ◽  
Vol 133 ◽  
Author(s):  
R. Darolia ◽  
D. F. Lahrman ◽  
R. D. Field ◽  
A. J. Freeman
Keyword(s):  
Room Temperature ◽  
Boundary Energy ◽  
Ternary Alloys ◽  
Total Electron ◽  
Solid Solution Strengthening ◽  
Band Structure Calculations ◽  
Solution Strengthening ◽  
Anti Phase Boundary ◽  
Structure Calculations ◽  
Electron Band Structure

ABSTRACTSingle crystals of stoichiometric NiAl and NiAl+V alloys were tested in compression and tension from room temperature to 871°C to determine deformation behavior. The dislocations were predominately <100> in the plastically deformed specimens. Attempts to ductilize NiAl by the addition of vanadium are described. The lowering of the anti-phase boundary energy by vanadium addition to NiAl, believed to promote the formation of <111> dislocations, was predicted by the all electron self consistent total electron band structure calculations. The vanadium additions caused considerable solid solution strengthening in NiAl, rendering the ternary alloys more brittle than stoichiometric NiAl.

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