The lamellar microstructure and fracture behavior of γ-based TiAl alloy produced by centrifugal spray deposition

1998 ◽  
Vol 247 (1-2) ◽  
pp. 126-134 ◽  
Author(s):  
W.Z Chen ◽  
X.P Song ◽  
K.W Qian ◽  
H.C Gu
Keyword(s):  
Fracture Behavior ◽  
Tial Alloy ◽  
Spray Deposition ◽  
Lamellar Microstructure

Effect of Heat Treatment on the Microstructure and Property of TiAl Alloys Prepared by Gas Atomization Powders

2013 ◽  
Vol 747-748 ◽  
pp. 497-501
Author(s):  
Na Liu ◽  
Zhou Li ◽  
Guo Qing Zhang ◽  
Hua Yuan ◽  
Wen Yong Xu ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Heat Treatment Temperature ◽  
Tial Alloy ◽  
Lamellar Microstructure ◽  
Treatment Temperature ◽  
Gas Atomization ◽  
Thermally Induced ◽  
Heat Treated ◽  
Fine Duplex ◽  
Step Heat Treatment

Powder metallurgical TiAl alloy was fabricated by gas atomization powders, and the effect of heat treatment temperature on the microstructure evolution and room tensile properties of PM TiAl alloy was investigated. The uniform fine duplex microstructure was formed in PM TiAl based alloy after being heat treated at 1250/2h followed by furnace cooling (FC)+ 900/6h (FC). When the first step heat treatment temperature was improved to 1360/1h, the near lamellar microstructure was achieved. The ductility of the alloy after heat treatment improved markedly to 1.2% and 0.6%, but the tensile strength decreased to 570MPa and 600MPa compared to 655MPa of as-HIP TiAl alloy. Post heat treatment at the higher temperature in the alpha plus gamma field would regenerate thermally induced porosity (TIP).

Effects of Preparation Processing on Mechanical Properties of TiAl Intermetallic

2007 ◽  
Vol 353-358 ◽  
pp. 1589-1592
Author(s):  
Wen Zhe Chen ◽  
Kai Ping Peng ◽  
Kuang Wu Qian
Keyword(s):  
Mechanical Properties ◽  
Tial Alloy ◽  
Spray Deposition ◽  
Ingot Metallurgy ◽  
Tial Alloys ◽  
Compression Properties ◽  
Different Temperatures ◽  
Strength And Plasticity ◽  
Increasing Temperature ◽  
The Relationship

Mechanical properties of the TiAl alloy produced by centrifugal spray deposition (CSD), compared to that produced by ingot metallurgy (IM), were investigated at different temperatures from 293 to 973K. The result shows that the ultimate strength, yield strength and plasticity of the CSD TiAl alloys, with excellent compression properties and plasticity, are higher than those of as-cast TiAl alloys at room temperature as well as at high temperature. There exists a critical temperature of 873K in the relationship between strength and temperature, in which strength increases with increasing temperature above 873K. The effects of CSD on mechanical properties of the TiAl alloy are discussed, and the higher strength with moderate ductility achieved is because of the finer lamellar structure got in the CSD processing, and this structure is also believed to be beneficial to ductility.

Erratum to “Microstructure determined fracture behavior of a high Nb containing TiAl alloy” [Mater. Sci. Eng. A 666 (2016) 297–304]

2017 ◽  
Vol 679 ◽  
pp. 554 ◽  
Author(s):  
Zeen Wu ◽  
Rui Hu ◽  
Tiebang Zhang ◽  
Huan Zhou ◽  
Hongchao Kou ◽  
...  
Keyword(s):  
Fracture Behavior ◽  
Tial Alloy

Influence of Microstructure and Stress Ratio on Fatigue Crack Propagation in TiAl Alloy

2014 ◽  
Vol 881-883 ◽  
pp. 1330-1333 ◽  
Author(s):  
Yan Rui Zuo ◽  
Zhi Yuan Rui ◽  
Rui Cheng Feng ◽  
De Chun Luo ◽  
Chang Feng Yan
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Stress Ratio ◽  
Tial Alloy ◽  
Lamellar Microstructure ◽  
Propagation Resistance ◽  
Crack Propagation Resistance ◽  
Stress Ratios ◽  
Fully Lamellar

Based on the fatigue crack propagation experiments did by A.-L. Gloanec et al., the fatigue crack propagation rates of TiAl alloy of two processing routes, namely casting and PM, and stress ratios had been tested, in order to find out the effects of microstructure and stress ratio. An improved fatigue crack propagation formula for region Ⅱ (the expansion region) was derived according to Paris formula. The specific values of the constants in the formula were calculated. Fatigue crack propagation resistance of nearly fully lamellar microstructure is superior to that of equiaxed γ grain. The experimental results present that both microstructure and stress ratio has a significant influence on fatigue crack growth rate.

Fracture Behavior of Directional TiAl Lamellar Structures

2011 ◽  
Vol 488-489 ◽  
pp. 634-637
Author(s):  
Ji Zhang
Keyword(s):  
Tensile Properties ◽  
Fracture Behavior ◽  
Detrimental Effect ◽  
Lamellar Microstructure ◽  
Griffith Crack ◽  
Lamellar Structures ◽  
Technology Improvement

In order to assess the influences of macro- and microstructure as well as the cast flaw on the tensile properties, the fracture behavior of a number of ambient tensile TiAl specimens containing directional lamellar microstructure have been analyzed. It is found that all the fractures of tensile specimens are triggered by a critical Griffith crack. According to the desirable ambient tensile properties coincide with the initial cracking facets smaller than 600 mm, it is proposed that the detrimental effect of the random oriented lamellar colonies on the tensile properties can be eliminated through cast technology improvement.

Cyclic Deformation of a Modern TiAl Alloy at High Temperatures

2014 ◽  
Vol 891-892 ◽  
pp. 1131-1136 ◽  
Author(s):  
Tomáš Kruml ◽  
Alice Chlupová ◽  
Karel Obrtlík
Keyword(s):  
Lamellar Structure ◽  
Tial Alloy ◽  
Low Cycle Fatigue ◽  
Lamellar Microstructure ◽  
Strain Curve ◽  
Cyclic Stress ◽  
Cyclic Softening ◽  
Fatigue Tests ◽  
Tensile Curve ◽  
Cyclic Straining

Ternary TiAl alloy with 8 at.% Nb and lamellar microstructure is subjected to low cycle fatigue tests at temperatures ranging from room temperature to 800 °C. The aim of the study is to find limit conditions when the microstructure is still stable and to study mechanisms of microstructural degradation when this limit is exceeded. Up to 750 °C, no cyclic softening or hardening is observed and cyclic stress-strain curve follows the tensile curve. Cyclic softening is characteristic for 800 °C. The TEM observation did not reveal any substantial changes in the microstructure due to the cycling up to 700°C. The lamellar structure is altered by cyclic straining at 750 °C and, to a higher extent, at 800°C. In specimens cycled to fracture at 800 °C, the domains without lamellar structure cover about 10% of volume and are almost dislocation free. The destruction of lamellar microstructure is the reason for the marked cyclic softening at 800 °C.

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