Ductilization of a Ni3(Si,Ti) Intermetallic Alloy by Addition of Interstitial Type Elements

2011 ◽  
Vol 409 ◽  
pp. 321-326
Author(s):  
Hisashi Kosaka ◽  
Yasuyuki Kaneno ◽  
Takayuki Takasugi
Keyword(s):  
Fracture Surface ◽  
Fracture Mode ◽  
Room Temperature ◽  
Tensile Ductility ◽  
Tensile Elongation ◽  
Intermetallic Alloy ◽  
Intermediate Temperature ◽  
Transgranular Fracture ◽  
Ti Alloy ◽  
Brittle Intergranular Fracture

The effect of a concomitant doping of interstitial type elements boron (B) and carbon (C), and boron (B) and nitrogen (N) on tensile properties of a Ni3(Si,Ti) intermetallic alloy was investigated in the temperature range between room temperature and 973 K. It was found that the concomitant doping of (C/B) and (N/B) remarkably improved the intermediate-temperature tensile elongation of the Ni3(Si,Ti) alloy compared with the simple doping of B or C. It was also shown that the fracture surface of the alloy doped with (C/B) and (N/B) exhibited the ductile transgranular fracture mode while that of the alloy doped with only B showed a brittle intergranular fracture mode at 773 K. These results clearly indicate that the concomitant doping of the interstitial type elements are useful for improving the intermediate-temperature tensile ductility of the Ni3(Si,Ti) alloy.

Fractography of Reaction-Sintered Si3N4

1980 ◽  
Vol 102 (2) ◽  
pp. 244-248
Author(s):  
M. G. Mendiratta ◽  
P. L. Land ◽  
R. Ruh ◽  
R. W. Rice ◽  
D. C. Larsen
Keyword(s):  
High Temperatures ◽  
Fracture Mode ◽  
Room Temperature ◽  
Size Range ◽  
Fracture Initiation ◽  
Transgranular Fracture ◽  
Four Point Bending ◽  
Fracture Appearance ◽  
Fracture Features

Fractography studies were accomplished on two reaction-sintered Si3N4 materials (Norton NC-350 Si3N4 and KBI (Kawecki-Berylco) Si3N4) which had been tested in four-point bending at room temperature, 1200, 1350, and 1500°C in air. At room temperature NC-350 exhibited uniform planar features representing a transgranular fracture mode, uniformly distributed small pores having a size range of 1–2 μm or less, and a few isolated large pores of ∼10 μm. In contrast, the KBI Si3N4 at room temperature exhibited nonuniform, diffuse, and ill-defined fracture features, small pores having a size range of 2–5 μm, and many large pores of ∼50 μm in size. At high temperatures, the fracture appearance of NC-350 Si3N4 was ill defined and diffuse, indicating a change in fracture mode. The fracture originating flaws in NC-350 were primarily the large pores or pore agglomerates. At all temperatures, in the KBI material, it was not possible to observe the mirror and, therefore, the site of fracture initiation. For NC-350, KIC values were 1.2–1.6 MN/m3/2 at room temperature and 2.1–2.4 MN/m3/2 at high temperatures.

Room Temperature Tensile Ductility in Powder Processed B2 FeAi Alloys

1986 ◽  
Vol 81 ◽  
Author(s):  
M. A. Crimp ◽  
K. M. Vedula ◽  
D. J. Gaydosh
Keyword(s):  
Fracture Surface ◽  
Yield Strength ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Cooling Rate ◽  
Yield Stress ◽  
Room Temperature ◽  
Tensile Ductility ◽  
Strengthening Mechanism ◽  
General Yielding

AbstractIt has been shown that it is possible to obtain significant room temperature tensile ductility in FeAl alloys using iron-rich deviations from stoichiometry. A comparison of the room temperature tensile and compressive behaviors of Fe−50at% Al and Fe−40at% Al shows that FeAl is brittle at higher Al contents because it fractures along grain boundaries before general yielding. Lower aluminium contents reduce the yield stress substantially and hence some ductility is observed before fracture.Addition of boron results in measurable improvements in ductility of Fe−40at% Al and is accompanied by an increase in transgranular tearing on the fracture surface, suggesting a grain boundary strengthening mechanism.Increasing the cooling rate following annealing at 1273 K results in a large increase in the yield strength and a corresponding decrease in ductility.

Anomalous Strain Rate Dependence of Tensile Elongation in Moisture-Embrittled L12 Alloys

2000 ◽  
Vol 646 ◽  
Author(s):  
T. Takasugi ◽  
Y. Kaneno ◽  
H. Inoue
Keyword(s):  
Strain Rate ◽  
Tensile Ductility ◽  
Tensile Elongation ◽  
Ultimate Tensile Stress ◽  
Fracture Pattern ◽  
Rate Dependence ◽  
Strain Rate Dependence ◽  
Transgranular Fracture ◽  
Air Oxidation ◽  
Ambient Temperatures

ABSTRACTThe effect of strain rate on tensile ductility of moisture-embrittled L12-type Co3Ti and Ni3(Si, Ti) ordered alloys was investigated at ambient temperatures (298K∼423K) by tensile test and SEM fractography. The anomalous increase of tensile elongation and ultimate tensile stress was observed in a low strain rate region and also at high temperatures, accompanied with an increased area fraction in ductile transgranular fracture pattern. The anomalous strain rate dependence of tensile ductility was shown to become more evident with decreasing grain size. As a process counteracting to the hydrogen decomposition from moisture in air, oxidation process on the alloy surface was suggested.

Improvement of Room Temperature Ductility of Ni3Al by Unidirectional Solidification

1990 ◽  
Vol 213 ◽  
Author(s):  
Toshiyuki Hirano ◽  
Sea-Sung Chung ◽  
Yoshinao Mishima ◽  
Tomoo Suzuki
Keyword(s):  
Room Temperature ◽  
Single Phase ◽  
Tensile Elongation ◽  
Growth Direction ◽  
Al Alloy ◽  
Transgranular Fracture ◽  
Zone Method ◽  
Room Temperature Ductility ◽  
The Matrix ◽  
Temperature Fracture

ABSTRACTWe present the new promising method to improve the ductility of intermetallic compound, Ni3Al. Stoichiometric and Alrich Ni3A1 were unidirectionally grown at the growth rate of 24 mm/h by a floating zone method (FZ-UDS). The stoichiometric Ni3Al had a columnar-grained and single phase structure, whereas the Al-rich Ni3Al had a Ni3Al matrix with martensite-like precipitates. These alloys exhibited a large tensile elongation along the growth direction at room temperature. Fracture mode is a complete transgranular fracture in the stoichiometric Ni 3Al alloy, and a mixture of transgranular fracture of the matrix and cleavage of the martensite-like precipitates with cracking at the phase boundary in the Al-rich Ni3Al alloys.

Mechanical Properties of 5052 Al Alloy Processed by Groove Pressing

2012 ◽  
Vol 468-471 ◽  
pp. 1831-1835
Author(s):  
Kai Huai Yang ◽  
Na Lin ◽  
Shao Feng Zeng ◽  
Wen Zhe Chen
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Fracture Surface ◽  
Surface Morphology ◽  
Fracture Mode ◽  
Room Temperature ◽  
Al Alloy ◽  
Fracture Surface Morphology ◽  
Annealed State

Three groups of commercial 5052 Al alloy sheets were subjected to groove pressing (GP) at room temperature using parallel GP, 180° cross GP and 90° cross GP, respectively. Mechanical properties and fracture modes of as-annealed and GPed samples were investigated. The microhardness of the samples processed by parallel GP increases by a factor of about 1.6 compared to the as-annealed state, and that of the samples processed by cross GP is higher. The ultimate tensile strength (UTS) increases significantly after GP, while the elongation decreases. But they are strongly dependence on the number of GP passes and the pressing modes. Besides, fracture surface morphology demonstrates that the fracture mode is ductile even after four passes. With increasing the number of GP pass, the amount of small dimples increases, and the dimples become shallow and more uniform.

scholarly journals Effects of Mo segregation on Charpy absorbed energy in Ti-12Mo alloys

2020 ◽  
Vol 321 ◽  
pp. 11050
Author(s):  
Satoshi Emura ◽  
Xin Ji ◽  
Xiaohua Min ◽  
Koichi Tsuchiya
Keyword(s):  
Room Temperature ◽  
Tensile Elongation ◽  
Solution Treatment ◽  
Charpy Impact ◽  
Transgranular Fracture ◽  
Omega Phase ◽  
Absorbed Energy ◽  
Rolled Sample ◽  
Heterogeneous Distribution ◽  
Charpy Absorbed Energy

Beta phase stabilizing elements such as Mo have strong tendency to segregate. We have introduced swirly type segregation of Mo in Ti-12Mo (mass %) alloy through groove bar rolling. After solution treatment and low temperature aging, hard omega phase was precipitated heterogeneously, which improved the room temperature tensile elongation values without sacrificing tensile strength. In this study, the effect of Mo segregation and heterogeneous distribution of omega phase on Charpy absorbed energy was investigated in Ti-12Mo alloy. Samples with two types of segregation were prepared; namely, swirly segregation in bar rolled sample and layered segregation in plate rolled sample. For comparison, we have also prepared Ti-12Mo bar samples with lesser Mo segregation, through high temperature thermomechanical treatment. Charpy impact tests were carried out at room temperature, 373 K and 473 K, respectively, using the samples after aging to introduce isothermal omega-phase. The samples with the segregation exhibited higher Charpy absorbed energy, especially at higher temperature of 473 K, while the sample with the swirly segregation showed higher Charpy absorbed energy than that with the layered segregation. The sample with lesser Mo segregation exhibited brittle intergranular fracture surface after Charpy testing. On the contrary, samples with Mo segregation exhibited ductile transgranular fracture surfaces.

Alloying Effect on the Environmental Embrittlement of Ni3(Si,Ti) Alloys

1994 ◽  
Vol 364 ◽  
Author(s):  
C. L. Ma ◽  
T. Takasugi ◽  
S. Hanada
Keyword(s):  
Room Temperature ◽  
Tensile Elongation ◽  
Tensile Tests ◽  
Distilled Water ◽  
Strain Rates ◽  
Ti Alloy ◽  
Transition Elements ◽  
Alloying Effect ◽  
Environmental Embrittlement ◽  
Ti Alloys

AbstractThe effect of additions of chromium, manganese and iron on environmental embrittlement of the Ni3(Si,Ti) alloy is investigated by room temperature tensile tests in various kind of atmospheres (vacuum, air, distilled water and H2 gas) and at various strain rates. The observed tensile elongation and the associated fracture mode are very much dependent on atmospheres and strain rates. It is shown that additions of these transition elements to the Ni3(Si,Ti) alloy are effective in reducing the embrittlement particularly in air and distilled water, and their magnitude of reducing the embrittlement decreased in the order, chromium, manganese and iron. However, additions of these transition elements are only slightly effective in reducing the embrittlement in H2 gas. The beneficial effect of additions of these transition elements on environmental embrittlement of the Ni3(Si,Ti) alloy is discussed, based on some possible mechanisms.

A Comparison between B4C-ZrB2-Al Composite and B4C-Al Composite on Microstructure and Mechanical Properties

2011 ◽  
Vol 279 ◽  
pp. 71-76 ◽  
Author(s):  
Peng Lü
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Fracture Surface ◽  
Flexural Strength ◽  
Fracture Mode ◽  
Transgranular Fracture ◽  
Aluminum Addition ◽  
Microstructure And Mechanical Properties ◽  
Al Composite ◽  
Toughness Improvement

B4C-Al and B4C-ZrB2-Al composites were fabricated by infiltrating aluminum into porous B4C and B4C-ZrB2 preforms in vacuum. The effect of ZrB2 addition on the microstucture and mechanical properties of the B4C-Al composites were investigated. The flexural strength and the fracture toughness of composite improved greatly as the result of ZrB2 addition. The ZrB2 addition inhibited the reaction between B4C and Al. The infiltrated aluminum addition was the leading reason for the fracture toughness improvement of the composites. Inter/transgranular fracture mode with many tear ridges and dimples was showing in the fracture surface of the B4C-ZrB2-Al composite. The relationships between the microstructures and the mechanical properties of the B4C-ZrB2-Al composites were discussed.

A Comparison between B4C-TiB2-Al Composite and B4C-Al Composite on Microstructure and Mechanical Properties

2011 ◽  
Vol 66-68 ◽  
pp. 255-259
Author(s):  
Peng Lü ◽  
Fang Yu ◽  
Hong Qiang Ru
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Fracture Surface ◽  
Flexural Strength ◽  
Fracture Mode ◽  
Transgranular Fracture ◽  
Aluminum Addition ◽  
Microstructure And Mechanical Properties ◽  
Al Composite ◽  
Toughness Improvement

B4C-Al and B4C-TiB2-Al composites were fabricated by infiltrating aluminum into porous B4C and B4C-TiB2preforms in vacuum. The effect of TiB2addition on the microstucture and mechanical properties of the B4C-Al composites were investigated. The flexural strength and the fracture toughness of composite improved greatly as the result of TiB2addition. The TiB2addition inhibited the reaction between B4C and Al. The infiltrated aluminum addition was the leading reason for the fracture toughness improvement of the composites. Inter/transgranular fracture mode with many tear ridges and dimples was showing in the fracture surface of the B4C-TiB2-Al composite. The relationships between the microstructures and the mechanical properties of the B4C-TiB2-Al composites were discussed.

Sign in / Sign up

Export Citation Format

Share Document