Deformation of an extruded nickel beryllide between room temperature and 820 °C

1991 ◽  
Vol 6 (12) ◽  
pp. 2653-2659 ◽  
Author(s):  
G.M. Pharr ◽  
S.V. Courington ◽  
J. Wadsworth ◽  
T.G. Nieh
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Elevated Temperature ◽  
Flow Stress ◽  
Strain Hardening ◽  
Room Temperature ◽  
High Temperature Strength ◽  
Compression Tests ◽  
Tension And Compression ◽  
Better Than

The mechanical properties of nickel beryllide, NiBe, have been investigated in the temperature range 20–820 °C. The room temperature properties were studied using tension, bending, and compression tests, while the elevated temperature properties were characterized in compression only. NiBe exhibits some ductility at room temperature; the strains to failure in tension and compression are 1.3% and 13%, respectively. Fracture is controlled primarily by the cohesive strength of grain boundaries. At high temperatures, NiBe is readily deformable—strains in excess of 30% can be achieved at temperatures as low as 400 °C. Strain hardening rates are high, and the flow stress decreases monotonically with temperature. The high temperature strength of NiBe is as good or better than that of NiAl, but not quite as good as CoAl.

Influence of Al-Cu-Mn-Fe-Ti Alloy Composition and Production Parameters of Extruded Semi-Finished Products on their Structure and Mechanical Properties

2017 ◽  
Vol 265 ◽  
pp. 456-462 ◽  
Author(s):  
P.L. Reznik ◽  
Mikhail Lobanov
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Thermal Treatment ◽  
Low Temperature ◽  
Room Temperature ◽  
High Temperature Strength ◽  
Ti Alloy ◽  
Low Temperature Annealing ◽  
Annealing Conditions ◽  
Concentration Changes

Studies have been conducted as to the effect of Cu, Mn, Fe concentration changes in Al-Cu-Mn-Fe-Ti alloy, the conditions of thermal and deformational treatment of ingots and extruded rods 40 mm in diameter on the microstructure, phase composition and mechanical properties. It has been determined that changing Al-6.3Cu-0.3Mn-0.17Fe-0.15Ti alloy to Al-6.5Cu-0.7Mn-0.11Fe-0.15Ti causes an increase in the strength characteristics of extruded rods at the room temperature both after molding and in tempered and aged conditions, irrespective of the conditions of thermal treatment of the initial ingot (low-temperature annealing 420 °С for 2 h, or high-temperature annealing at 530 °С for 12 h). Increasing the extruding temperature from 330 to 480 °С, along with increasing Cu, Mn and decreasing Fe in the alloy Al-Cu-Mn-Ti, is accompanied by the increased level of ultimate strength in a quenched condition by 25% to 410 MPa, irrespective of the annealing conditions of the original ingot. An opportunity to apply the Al-6.3Cu-0.3Mn-0.17Fe-0.15Ti alloy with low-temperature annealing at 420 °С for 2 h and the molding temperature of 330 °С has been found to produce rods where, in the condition of full thermal treatment (tempering at 535 °С + aging at 200 °С for 8 hours), a structure is formed that ensures satisfactory characteristics of high temperature strength by resisting to fracture for more than 100 hours at 300 °С and 70 MPa.

A Method for the Production of Large Sized Al-B4C-Al2O3np Nanocomposites through Liquid-State Process

2017 ◽  
Vol 753 ◽  
pp. 84-92
Author(s):  
Wei Liu ◽  
Qiu Lin Li ◽  
Wei Liu ◽  
Guo Gang Shu ◽  
Qi Sun ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Elevated Temperature ◽  
Ball Milling ◽  
Liquid State ◽  
Room Temperature ◽  
Milling Time ◽  
Mixed Powder ◽  
State Process ◽  
Semi Solid

The paper introduces a new method to produce large sized Al-B4C-Al2O3np composites, which combines ball milling to prepare Al2O3np/Al mixed powder and semi-solid casting to contribute the injection of Al2O3np/Al mixed powder into the melt. The deformation performance of Al2O3np and micro-Al through ball milling with different Al/Al2O3np ratios, different milling time and different balls were studied respectively. It was revealed that micro-Al particles were milled from twisted and crimpled foil pieces to shuttles with Al2O3np embedded on it through 4h milling with 10mm balls. And we consider it as the best bonding between Al2O3np and micro-Al we could attain. And a plate of 25kg of Al-B4C-Al2O3np composite was fabricated successfully with the injection of the Al2O3np/Al mixed powder. Spherical Al2O3np of 300nm and needle-like TiB2 with 200nm in radius and 800nm-4μm in length were found in SEM photographs. Tensile properties of Al-B4C-Al2O3np composites were tested at room temperature and high temperature. It was showed higher mechanical properties than Al-B4C composites at room temperature and elevated temperature. Particularly, a 40% increase of UTS of Al-15wt.% B4C-1wt.%Al2O3np at 350°C was observed.

Processing, mechanical properties and oxidation behavior of TaC and HfC composites containing 15 vol% TaSi2 or MoSi2

2009 ◽  
Vol 24 (6) ◽  
pp. 2056-2065 ◽  
Author(s):  
Diletta Sciti ◽  
Laura Silvestroni ◽  
Stefano Guicciardi ◽  
Daniele Dalle Fabbriche ◽  
Alida Bellosi
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
High Temperature ◽  
Mechanical Strength ◽  
Hot Pressing ◽  
Room Temperature ◽  
Oxidation Behavior ◽  
Temperature Stability ◽  
High Temperature Stability ◽  
Better Than

Fully dense HfC and TaC-based composites containing 15 vol% TaSi2 or MoSi2 were produced by hot pressing at 1750–1900 °C. TaSi2 enhanced the sinterability of the composites and nearly fully dense materials were obtained at lower temperatures than in the case of MoSi2-containing ones. The TaC-based composites performed better than HfC composites at room temperature, showing values of mechanical strength up to 900 MPa and a fracture toughness of 4.7 MPa·m1/2. However, preliminary oxidation tests carried out in air at 1600 °C revealed that HfC-based composites have a superior high temperature stability compared to TaC-based materials.

Effect of Zr Addition on High Temperature Mechanical Properties of Near Alpha Ti-Al-Zr-Sn Based Alloy

2014 ◽  
Vol 783-786 ◽  
pp. 580-583 ◽  
Author(s):  
Murugesan Jayaprakash ◽  
De Hai Ping ◽  
Y. Yamabe-Mitarai
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Room Temperature ◽  
High Temperature Strength ◽  
Test Results ◽  
High Temperature Mechanical Properties ◽  
Ti Alloys ◽  
Zr Addition ◽  
And Performance ◽  
Compressive Tests

Titanium (Ti) alloys are widely used in aerospace industries successfully up to 600°C. Increasing the operating temperature and performance of these alloys would be very useful for fuel economy. Numerous numbers of research works has been focused on the improvement of the high temperature performances of Ti alloys. It has been well known that Zirconium (Zr) is one of the important solid-solution strengthener in Ti-alloys. In the present study, the effect of Zr addition on the microstructure and mechanical properties of the near–α Ti-Al-Zr-Sn based alloys has been investigated.The compression test results showed that Zr addition significantly improves both room temperature and high temperature strength. The results obtained were explained based on the microstructural observation, room temperature and high temperature compressive tests.

Influence of Interfacial Characteristics on the Mechanical Properties of Continuous Fiber Reinforced Nial Composites

1992 ◽  
Vol 273 ◽  
Author(s):  
Randy R. Bowman
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Thermal Cycling ◽  
Oxidation Resistance ◽  
Cyclic Oxidation ◽  
Room Temperature ◽  
Matrix Cracking ◽  
High Temperature Strength ◽  
Interfacial Bond ◽  
The Matrix

ABSTRACTAs part of a study to assess NiAl-based composites as potential high-temperature structural materials, the mechanical properties of polycrystalline NiAl reinforced with 30 vol.% continuous single crystal Al2O3 fibers were investigated. Composites were fabricated with either a strong or weak bond between the NiAl matrix and Al2O3 fibers. The effect of interfacial bond strength on bending and tensile properties, thermal cycling response, and cyclic oxidation resistance was examined. Weakly-bonded fibers increased room-temperature toughness of the composite over that of the matrix material but provided no strengthening at high temperatures. With effective load transfer, either by the presence of a strong interfacial bond or by remotely applied clamping loads, Al2O3 fibers increased the high-temperature strength of NiAl but reduced the strain to failure of the composite compared to the monolithic material. Thermal cycling of the weakly-bonded material had no adverse effect on the mechanical properties of the composite. Conversely, because of the thermal expansion mismatch between the matrix and fibers, the presence of a strong interfacial bond generated residual stresses in the composite that lead to matrix cracking. Although undesirable under thermal cycling conditions, a strong interfacial bond was a requirement for achieving good cyclic oxidation resistance in the composite. In addition to the interfacial characterization, compression creep and room temperature fatigue tests were conducted on weakly-bonded NiAl/Al2O3 composites to further evaluate the potential of this system. These results demonstrated that the use of A12O3 fibers was successful in improving both creep and fatigue resistance.

Mechanical Properties and Microstructure of Certain Niaico(Hf) Alloys

1990 ◽  
Vol 186 ◽  
Author(s):  
S. M. Russell ◽  
C. C Law ◽  
L. S. Lin ◽  
G. W. Levan
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Martensitic Transformation ◽  
Low Temperatures ◽  
Creep Resistance ◽  
Room Temperature ◽  
Hexagonal Structure ◽  
High Temperature Strength ◽  
Room Temperature Ductility ◽  
Poor Creep Resistance

AbstractCobalt-modified NiAl alloys are being studied for their potential for room temperature ductility and toughness. An alloy of Ni - 29.3 a/o Al - 36.7 a/o Co has shown improved toughness and ductility with respect to binary NiAl alloys due in part to a stress-induced martensitic transformation. Furthermore, the cobalt additions have altered the slip behavior to {110}<111> type from {110} <001> for binary NiAl alloys. Hafnium was added to improve the alloy's relatively poor creep resistance and high temperature strength. Hf was found to be insoluble in the NiAlCo alloy and formed precipitates with a hexagonal structure. The Hfmodified alloy had improved high temperature strength. In addition, the Hf apparently changed the creep mechanism resulting in poorer creep resistance at low temperatures, but improved creep resistance at higher stresses and temperatures.

Elevated temperature creep properties of NiAl eryomilled with and without Y2O3

1995 ◽  
Vol 10 (5) ◽  
pp. 1171-1186 ◽  
Author(s):  
J. Daniel Whittenberger ◽  
Michael J. Luton
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Stress Exponent ◽  
Tensile Testing ◽  
High Stress ◽  
Tensile Creep ◽  
High Temperature Strength ◽  
Compression Tests ◽  
Creep Properties

The creep properties of lots of NiAl eryomilled with and without Y2O3 have been determined in compression and tension. Although identical cryomilling procedures were used, differences in composition were found between the lot ground with 0.5 vol % yttria and the lot ground without Y2O3. Compression testing between 1000 and 1300 K yielded similar crecp strengths for both materials, while tensile creep rupture testing indicated that the yttria-containing alloy was slightly stronger than the Y2O3-free version. Both compression and tensile testing showed two deformation regimes; whereas the stress state did not affect the high stress exponent (n ≍ 10) mechanism, the low stress exponent regime n was ∼6 in tension and ∼2 in compression. The strengths in tension were somewhat less than those measured in compression, but the estimated activation energies (Q) of ∼600 kJ/mol for tensile testing were closer to the previously measured values (∼700 kJ/mol) for NiAl-AlN and very different from the Q's of 400 and 200 kJ/mol for compression tests in the high and low stress exponent regimes, respectively. A Larson-Miller comparison indicated that cyromilling can produce an alloy with long-term, high-temperature strength at least equal to conventional superalloys.

Performance Analysis of Fire-Resistant H-Beam Steel

2010 ◽  
Vol 163-167 ◽  
pp. 2949-2952
Author(s):  
Jian Qing Qian ◽  
Ji Ping Chen ◽  
Bao Qiao Wu ◽  
Jie Ca Wu
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Chemical Composition ◽  
Room Temperature ◽  
High Temperature Strength ◽  
High Temperature Mechanical Properties ◽  
H Beam ◽  
Hot Rolled ◽  
Very High ◽  
Room Temperature Strength

The fire-resistant hot-rolled H-beam steel is the newly developed structure material. The development situation of the fire-resistant H-beam steel is briefly introduced. The chemical composition, microstructure, room temperature and high temperature mechanical properties and weldability of several batches of the developed domestic fire-resistant hot-rolled H-beam steels are comprehensively analyzed. The results show that the newly developed hot-rolled fire-resistant H-beam steel has very high room temperature strength, certain high temperature strength, good welding performance, but the toughness needs to be further improved. The performance of web and flange of H-beam steel has large gap.

Effects of Alloying Elements on the Temperature Dependence of Yield Stress in L12-Co3(Al,W)

2015 ◽  
Vol 1760 ◽  
Author(s):  
Zhenghao M. T. Chin ◽  
Norihiko L. Okamoto ◽  
Haruyuki Inui
Keyword(s):  
High Temperature ◽  
Temperature Dependence ◽  
Yield Stress ◽  
Room Temperature ◽  
Single Phase ◽  
Alloying Elements ◽  
High Temperature Strength ◽  
Positive Temperature ◽  
Compression Tests ◽  
Polycrystalline Alloys

ABSTRACTThe effects of alloying elements (Ni/Ta) on the temperature dependence of yield stress in Co3(Al,W) with the L12 structure have been investigated through compression tests of nearly single-phase polycrystalline alloys in the temperature range between room temperature to 1,473K. Compared with a ternary Co3(Al,W), a Ni/Ta-added Co3(Al,W) alloy exhibits a higher γ΄ solvus temperature and lower onset temperature of the yield stress anomaly (positive temperature dependence of yield stress), suggesting that the CSF energy is increased by Ni/Ta addition. As a consequence, the high-temperature strength in Co3(Al,W) is considerably enhanced.

Tensile Properties of Cast and Hot Isostatic Pressurized Ti-6Al-4Fe-xSi Alloys

2004 ◽  
Vol 449-452 ◽  
pp. 689-692
Author(s):  
E.H. Kim ◽  
Hi Won Jeong ◽  
Seung Eon Kim ◽  
Yong Taek Hyun ◽  
Yont Tai Lee ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Tensile Properties ◽  
Room Temperature ◽  
Precipitation Hardening ◽  
Low Cost ◽  
High Strength ◽  
Alloy System ◽  
High Temperature Mechanical Properties ◽  
Better Than

A new high strength titanium alloy system with low cost alloying elements, such as Al, Fe, has been recently developed. In present study the expensive V was replaced with Fe, and Si was added from 0 to 7.5wt.%. The effect of Fe and Si on the microstructure and tensile properties of Ti-6Al-4Fe-xSi (x=0, 0.1, 0.25, 0.5, 0.75wt.%) alloys was investigated. The room and high temperature mechanical properties of Ti-6Al-4Fe alloys were better than those of the Ti-6Al-4V. It was mainly due to the phase boundary strengthening at ambient and high temperature. The strength and elongation of the developed alloys depended upon the Si contents. The Si elements made the grain boundary and colony size fine, and increased the strength of the developed alloys by solid solution and precipitation hardening. The tensile strength variation with the Si contents at room temperature and 400°C, and at 450°C and 500°C showed a similar behavior, respectively.

Sign in / Sign up

Export Citation Format

Share Document