Mechanical properties of As-cast and directionally solidified Nb-Mo-W-Ti-Si in-situ composites at high temperatures

2003 ◽  
Vol 34 (1) ◽  
pp. 85-94 ◽  
Author(s):  
Jiangbo Sha ◽  
Hisatoshi Hirai ◽  
Hidetoshi Ueno ◽  
Tatsuo Tabaru ◽  
Akira Kitahara ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Temperatures ◽  
Directionally Solidified ◽  
In Situ Composites

Microstructure Evolution and Compression Properties of a Directionally Solidified Ni-24.8%Nb Hypereutectic Alloy

2010 ◽  
Vol 654-656 ◽  
pp. 1351-1354
Author(s):  
Shuang Ming Li ◽  
Bing Lun Jiang ◽  
Heng Zhi Fu
Keyword(s):  
Mechanical Properties ◽  
Microstructure Evolution ◽  
Growth Velocity ◽  
Thermal Gradient ◽  
Hypereutectic Alloy ◽  
Directionally Solidified ◽  
In Situ Composites ◽  
Compression Properties ◽  
Deformation Behaviors

At normal solidification conditions, in-situ composites of a Ni-24.8%Nb hypereutectic alloy can be produced at growth velocities below 5μm/s, with a thermal gradient of 180K/cm, and this low productivity remarkably restricts the application of this kind of in-situ composites. In this paper, we proposed an approach that employs an abrupt growth velocity to make the in-situ composites grow stably out of the coupled zone. In-situ composites of the Ni-24.8%Nb hypereutectic alloy were obtained at a growth velocity of 100μm/s and the productivity was greatly improved. This value is in the same order magnitude imposed on the single-crystal superalloys. The compression strengths were investigated on different microstructures involving the coupled eutectics and non-coupled eutectics. The results showed that the crack distribution and extension were mainly localized in primary Ni3Nb dendrites in the non-coupled eutectics, and that in-situ composites with the entirely coupled eutectics have improved mechanical properties and different deformation behaviors.

The effect of Hf and Ti additions on microstructure and properties of Cr2Nb–Nb in situ composites

1996 ◽  
Vol 11 (8) ◽  
pp. 1917-1922 ◽  
Author(s):  
B.P. Bewlay ◽  
M. R. Jackson
Keyword(s):  
Mechanical Properties ◽  
Tensile Properties ◽  
Laves Phase ◽  
Directionally Solidified ◽  
Two Phase ◽  
In Situ Composites ◽  
Niobium Silicide ◽  
Microstructure And Properties ◽  
Two Phases

The present paper describes the effect of Hf and Ti additions on the microstructures and mechanical properties of two-phase composites based on the Cr2Nb–Nb eutectic. The microstructures of directionally solidified in situ composites containing 50–70% by volume of the Laves phase Cr2Nb which was modified with Hf (7.5–9.2%) and Ti (16.5–26%) are described. Partitioning of Hf and Ti between the two phases is discussed using microprobe and EDS results. The tensile properties at 1100 and 1200 °C are described and compared with those of an analogous niobium silicide-based composite. The Cr2(Nb)–(Nb) composite tensile yield strengths at 1200 °C were increased over that of monolithic Cr2Nb to ∼130 MPa. However, at 1200 °C the yield strengths of the silicide-based composites were approximately twice those of the Cr2(Nb)–(Nb) composites.

Fabrication, characterization and analysis of improvements in mechanical properties of AA7075/ZrB2 in-situ composites

Measurement ◽  
2019 ◽  
Vol 136 ◽  
pp. 356-366 ◽  
Author(s):  
M. Nallusamy ◽  
S. Sundaram ◽  
K. Kalaiselvan
Keyword(s):  
Mechanical Properties ◽  
In Situ Composites

Microstructural characterization and mechanical properties of Nb–Ti–C–B in-situ composites with W addition

2015 ◽  
Vol 646 ◽  
pp. 332-340 ◽  
Author(s):  
Xinjiang Zhang ◽  
Yibin Li ◽  
Xiaodong He ◽  
Xueran Liu ◽  
Qiong Jiang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Microstructural Characterization ◽  
In Situ Composites

Mechanical properties of NiAl-Mo composites produced by specially controlled directional solidification

2012 ◽  
Vol 1516 ◽  
pp. 255-260 ◽  
Author(s):  
G. Zhang ◽  
L. Hu ◽  
W. Hu ◽  
G. Gottstein ◽  
S. Bogner ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Directional Solidification ◽  
Creep Resistance ◽  
Room Temperature ◽  
Growth Direction ◽  
Nominal Composition ◽  
Potential Candidate ◽  
In Situ Composites

ABSTRACTMo fiber reinforced NiAl in-situ composites with a nominal composition Ni-43.8Al-9.5Mo (at.%) were produced by specially controlled directional solidification (DS) using a laboratory-scale Bridgman furnace equipped with a liquid metal cooling (LMC) device. In these composites, single crystalline Mo fibers were precipitated out through eutectic reaction and aligned parallel to the growth direction of the ingot. Mechanical properties, i.e. the creep resistance at high temperatures (HT, between 900 °C and 1200 °C) and the fracture toughness at room temperature (RT) of in-situ NiAl-Mo composites, were characterized by tensile creep (along the growth direction) and flexure (four-point bending, vertical to the growth direction) tests, respectively. In the current study, a steady creep rate of 10-6s-1 at 1100 °C under an initial applied tensile stress of 150MPa was measured. The flexure tests sustained a fracture toughness of 14.5 MPa·m1/2at room temperature. Compared to binary NiAl and other NiAl alloys, these properties showed a remarkably improvement in creep resistance at HT and fracture toughness at RT that makes this composite a potential candidate material for structural application at the temperatures above 1000 °C. The mechanisms responsible for the improvement of the mechanical properties in NiAl-Mo in-situ composites were discussed based on the investigation results.

scholarly journals Fabrication and mechanical properties of Al2O3/TiAl in situ composites doped with Nb2O5

2015 ◽  
Vol 47 (3) ◽  
pp. 311-317 ◽  
Author(s):  
F. Wang ◽  
N. Fan ◽  
J. Zhu ◽  
H. Jiang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Hot Press ◽  
Dispersion Method ◽  
Powder Mixtures ◽  
In Situ Composites ◽  
Microstructures And Mechanical Properties

Al2O3/TiAl composites were successfully fabricated from powder mixtures of Ti, Al, TiO2, Cr2O3 and Nb2O5 by a hot-press-assisted exothermic dispersion method. The effect of the Cr2O3 and Nb2O5 addition on the microstructures and mechanical properties of Al2O3/TiAl composites was characterized. The results showed that the specimens are mainly composed of TiAl, Ti3Al, Al2O3, NbAl3 and Cr2Al. The Vicker-hardness and density of Al2O3/TiAl composites increase gradually with the increase of Nb2O5 content. When the Nb2O5 content was 6.54 wt %, the flexural strength and fracture toughness of the composites have a maximum values of 789.79 MPa and 9.69 MPa?m1/2, respectively. The improvement of mechanical properties is discussed in detail.

Processing and mechanical properties of in-situ composites from the NiAlCr and the NiAl(Cr,Mo) eutectic systems

1995 ◽  
Vol 3 (2) ◽  
pp. 99-113 ◽  
Author(s):  
D.R. Johnson ◽  
X.F. Chen ◽  
B.F. Oliver ◽  
R.D. Noebe ◽  
J.D. Whittenberger
Keyword(s):  
Mechanical Properties ◽  
In Situ Composites ◽  
Eutectic Systems
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