scholarly journals Study on the Relationship between High Temperature Mechanical Properties and Precipitates Evolution of 7085 Al Alloy after Long Time Thermal Exposures

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1483
Author(s):  
Jinxin Zang ◽  
Pan Dai ◽  
Yanqing Yang ◽  
Shuai Liu ◽  
Bin Huang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Electrical Conductivity ◽  
High Temperature ◽  
Tensile Properties ◽  
Volume Fraction ◽  
Al Alloy ◽  
Strengthening Effect ◽  
Nano Scale ◽  
High Temperature Mechanical Properties ◽  
The Relationship

The requirement for 7085 Al alloy as large airframe parts has been increasing due to its low quenching sensitivity and high strength. However, the relationship between high temperature mechanical properties and the evolution of precipitates in hot environments is still unclear. In this work, thermal exposure followed by tensile tests were conducted on the 7085 Al alloy at various temperatures (100 °C, 125 °C, 150 °C and 175 °C). Variations of hardness, electrical conductivity and tensile properties were investigated. The evolution of the nano scale precipitates was also quantitatively characterized by transmission electron microscopy (TEM). The results show that the hardness and electrical conductivity of the alloy are more sensitive to the temperature than to the time. The strength decreases continuously with the increase of temperature due to the transformation from η′ to η phase during the process. Furthermore, the main η phase in the alloy transformed from V3 and V4 to V1 and V2 variants when the temperature was 125 °C. Additionally, with increasing the temperature, the average precipitate radius increased, meanwhile the volume fraction and number density of the precipitates decreased. The strengthening effect of nano scale precipitates on tensile properties of the alloy was calculated and analyzed.

scholarly journals Experimental study on high temperature mechanical properties of aluminate cement mortar mixed with fiber

2021 ◽  
Vol 25 (6 Part B) ◽  
pp. 4441-4448
Author(s):  
Ping Xu ◽  
Dong Han ◽  
Jian-Xin Yu ◽  
Yu-Hao Cui ◽  
Min-Xia Zhang
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Flexural Strength ◽  
Volume Fraction ◽  
Cement Mortar ◽  
Steel Fibers ◽  
Basalt Fibers ◽  
High Temperature Mechanical Properties ◽  
Micro Structures ◽  
Aluminate Cement

The aim of the present paper is to study the mechanical properties of aluminate cement mortar mixed with different chopped fibers under high temperature. The specimens with a size of 40 mm ? 40 mm ? 160 mm is treated at various tempera?tures of 25?C, 200?C, 400?C, 600?C, and 800?C. The compressive and flexural strength of the aluminate cement mortar and its micro-structures are tested. The results show that the chopped steel fibers and basalt fibers are effective in improv?ing the high temperature mechanical properties of aluminate cement mortar. When the volume fraction of chopped steel fibers is 2%, the compressive strength and flexural strength of the test block treated at the temperature of 800?C increase by 18.3% and 128.6%, respectively.

The Effect of Microalloying B on the High Temperature Mechanical Properties of Ti3Al

1988 ◽  
Vol 133 ◽  
Author(s):  
Joseph W. Newkirk ◽  
Gerald B. Feldewerth
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Tensile Properties ◽  
Grain Refinement ◽  
High Temperature Mechanical Properties ◽  
High Temperature Tensile ◽  
High Temperature Tensile Properties

ABSTRACTThe effect of adding boron to Ti3Al on the microstructure and high temperature tensile properties has been studied. Boron caused a large grain refinement that dominated the tensile properties at all temperatures. Particles of Ti2B were found in all of the boron containing alloys. TiB was found only at concentrations of 0.1% B or more.

scholarly journals The Effect of the Cooling Rates on the Microstructure and High-Temperature Mechanical Properties of a Nickel-Based Single Crystal Superalloy

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4256
Author(s):  
Xiao-Yan Wang ◽  
Meng Li ◽  
Zhi-Xun Wen
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Single Crystal ◽  
Solution Treatment ◽  
Single Crystal Superalloy ◽  
Air Cooling ◽  
Strengthening Effect ◽  
Cooling Rates ◽  
High Temperature Mechanical Properties ◽  
High Temperature Tensile

The as-cast alloy of nickel-based single-crystal superalloy was used as the research object. After four hours of solution treatment at 1315 °C, four cooling rates (water cooling (WC), air cooling (AC) and furnace cooling (FC1/FC2)) were used to reduce the alloy to room temperature. Four different microstructures of nickel-based superalloy material were prepared. A high-temperature tensile test at 980 °C was carried out to study the influence of various rates on the formation of the material’s microstructure and to further obtain the influence of different microstructures on the high-temperature mechanical properties of the materials. The results show that an increase of cooling rate resulted in a larger γ′ phase nucleation rate, formation of a smaller γ′ phase and a greater number. When air cooling was used, the uniformity of the γ′ phase and the coherence relationship between the γ′ phase and the γ phase were the best. At the same time, the test alloy had the best high-temperature tensile properties, and the material showed a certain degree of plasticity. TEM test results showed that the test alloy mainly blocked dislocations from traveling in the material through the strengthening effect of γ′, and that AC had the strongest hindering effect on γ′ dislocation movement.

An Investigation on Duplex Nucleation in AZ91 Magnesium Alloy and Its Influence on High Temperature Mechanical Properties

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
A. Saber ◽  
R. Haghayeghi ◽  
H. Najafi ◽  
Peiman Shahbeigi-Roodposhti
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Grain Refinement ◽  
Al Alloy ◽  
Grain Refiner ◽  
Az91 Magnesium Alloy ◽  
High Temperature Mechanical Properties ◽  
Nucleation Sites ◽  
Refinement Mechanism ◽  
Carbon Inoculation

The grain refinement of Mg–Al alloy AZ91 via carbon inoculation, including the significant role of Mn in advanced nucleation, was analyzed, and the corresponding mechanical properties and aging behavior were investigated. To this end, various amounts of C were added into the liquid at the desired temperatures. Al8Mn5 particles, which are suitable nucleation sites for α-Mg, were identified as the primary grain refiners. In situ particle formation, along with appropriate wetting and a suitable orientation relationship (OR), facilitated the grain refinement mechanism. Al4C3 particles contributed to heterogeneous nucleation by providing suitable Al8Mn5 nucleation sites. Mn removal resulted in poor grain refinement in the Mg–Al alloy. The Hall–Petch relationship, high-temperature tensile behavior, and aging mechanism of the samples refined by 1 wt % C addition (as the best grain refiner) are discussed and compared with industrial practice.

Correlation of Strength with Hardness and Electrical Conductivity for Aluminium Alloy 7010

2006 ◽  
Vol 519-521 ◽  
pp. 853-858 ◽  
Author(s):  
Manuel A. Salazar-Guapuriche ◽  
Y.Y. Zhao ◽  
Adam Pitman ◽  
Andrew Greene
Keyword(s):  
Mechanical Properties ◽  
Electrical Conductivity ◽  
Tensile Strength ◽  
Aluminium Alloy ◽  
Precipitation Hardening ◽  
Age Hardening ◽  
Al Alloy ◽  
Wide Range ◽  
Proof Strength ◽  
The Relationship

The tensile strength, proof strength, hardness and electrical conductivity of Al alloy 7010 under different temper and ageing conditions were investigated with the aim to correlate strength with hardness and electrical conductivity so that the strength of the alloy can be determined nondestructively. Following the solutionising treatment, continuous age hardening was performed on a series of test coupons, taken from a large plate, to produce a wide range of precipitation hardening conditions, which gave rise to progressive variations of strength, hardness and conductivity. The relationship between strength and hardness was found to be reasonably linear, whereas the relationship between hardness and strength with electrical conductivity was non-linear. The ageing conditions and therefore the mechanical properties of the components can be predicted more accurately by the simultaneous combination of hardness and conductivity values.

High-Temperature Tensile Properties of Ti-Al-X (X=Cr,W) Consisting of α2, β and γ in Three Phases

2012 ◽  
Vol 706-709 ◽  
pp. 1066-1070 ◽  
Author(s):  
Keizo Hashimoto
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Tensile Properties ◽  
Titanium Aluminides ◽  
Turbine Blades ◽  
Solid Solution Hardening ◽  
High Temperature Mechanical Properties ◽  
Fine Grain ◽  
Super Plastic ◽  
Three Phases

Gamma titanium aluminides (γ-TiAl) have been investigated extensively for more than 25 years, since they are considered to be candidate materials for advanced jet engine components, automobile exhaust valves, turbo-chargers, and so on. Many researchers have reported that the mechanical properties of γ-TiAl have been improved by micro-alloying and thermo-mechanical microstructure control. Recently, γ-TiAl entered a new era by being applied to low-pressure turbine blades in newly developed commercial jet engines. In order to spread their applications further, material durability and affordability have become key issues. The tensile properties of the Ti-Al-X (X=Cr or W) have been studied intensively at various strain rates and test temperatures in a vacuum atmosphere. It has been demonstrated that the additions of a few atomic percent of Cr or W to γ-TiAl shifts the phase stability drastically and creates relatively fine-grain microstructures consisting of α2+β+γ in three phases. Although the microstructures of Ti-46at%Al-2.7at%Cr and Ti-45at%Al-1.9at%W show similar morphology, the high-temperature mechanical properties of each indicate distinguishable properties. The former specimens have demonstrated the capability of super-plastic deformation at temperatures above 1323K; the latter specimens, however, have showed relatively higher tensile strength than those of the other specimens having ternary compositions (Ti-Al-X). The differences in the tensile properties of Ti-Al-X (X=Cr or W) have been discussed in conjunction with microstructures and the effects of solid-solution hardening due to W atoms.

Effects of Nb on the High Temperature Mechanical Properties of TiNiAl Alloys

2007 ◽  
Vol 546-549 ◽  
pp. 1477-1480 ◽  
Author(s):  
Gao Song Qiu ◽  
Xin Qing Zhao ◽  
Ling Jie Meng ◽  
Hui Bin Xu
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Yield Strength ◽  
Yield Stress ◽  
Microstructure Evolution ◽  
High Yield ◽  
Strengthening Effect ◽  
High Temperature Mechanical Properties ◽  
Solution Strengthening ◽  
Nb Addition

A series of NiTiAl based alloys with different amount of Nb addition were prepared and the effects of Nb on both the mechanical properties and microstructure evolution were investigated. The addition of Nb can remarkably enhance the high temperature yield strength of these alloys. The highest yield strength of the alloys with 10 at% Nb reaches 1237MPa at 873K and 875MPa at 973K, respectively. The Ti2Ni(Al,Nb) precipitates and the solution strengthening effect might be responsible for the high yield stress achieved at high temperature.

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.

Influences of Al, Ce on the Microstructure and Mechanical Properties of As-Cast Mg-6Zn Alloy

2013 ◽  
Vol 747-748 ◽  
pp. 470-477
Author(s):  
Rui Dong Liu ◽  
Xu Guang Dong ◽  
Fu Jun Wei ◽  
Yuan Sheng Yang
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Yield Strength ◽  
Ultimate Strength ◽  
Magnesium Alloys ◽  
Room Temperature ◽  
Volume Fraction ◽  
High Temperature Mechanical Properties ◽  
Microstructure And Mechanical Properties ◽  
Al Addition

The effects of minor Al and Ce on the microstructures, room-temperature and high-temperature mechanical properties of as-cast Mg-6Zn magnesium alloys were investigated. With the Al addition into Mg-6Zn alloy, the coarse eutectic Mg51Zn20phases were refined and distributed discontinuously. After adding 0.5wt.% Ce into Mg-6Zn-1Al alloy, a new needle-like Al2CeZn2phase was observed. Meanwhile, the volume fraction of Mg51Zn20phase decreased and the semi-continuous Mg51Zn20phase became discontinuous globular morphology. It has been observed that the addition of Ce element coarsens the grains, and 1wt.% Al addition enhanced the yield strength and ultimate strength from 86.35MPa, 229MPa to 90.7MPa, 238MPa, respectively. Moreover, the Ce addition can significantly increase the high-temperature mechanical properties of cast Mg-6Zn-1Al alloy.

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