scholarly journals Novel Application Research on Critical High-Temperature Deformation of Low-Lead Brass Alloy

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 722
Author(s):  
Kuan-Jen Chen
Keyword(s):  
High Temperature ◽  
High Strain ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Application Research ◽  
Brass Alloy ◽  
Alloy Matrix ◽  
Β Phase ◽  
High Strain Rate Deformation

This study investigated the critical high-temperature deformation of the low-lead (Pb) Cu38Zn3Pb alloy. Moreover, the dezincification mechanism of this alloy for high-temperature applications was evaluated. The results reveal that tensile temperatures influence the phase structures of the brass alloy matrix. Many voids and holes formed at the phase boundaries above 400 °C due to the hard-brittle β’ phase which transformed into the softer β phase, thus causing low-strength and high-ductility values. High strain rate deformation promotes more obvious intermediate-temperature brittleness in the brass alloy. The Cu38Zn3Pb alloys display the lowest impact toughness between 400 °C and 600 °C. Long-term hot working caused dezincification in the brass alloy, thus deteriorating its ductility. The influences of thermal dezincification on the mechanical properties of the alloy must be considered during processing or heat treatment.

scholarly journals Fly Ash Utilisation in Mullite Fabrication: Development of Novel Percolated Mullite

Minerals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 84
Author(s):  
Pramod Koshy ◽  
Naomi Ho ◽  
Vicki Zhong ◽  
Luisa Schreck ◽  
Sandor Alex Koszo ◽  
...  
Keyword(s):  
High Temperature ◽  
Fly Ash ◽  
Mineral Resources ◽  
Nucleating Agent ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Stable Phase ◽  
Power Stations ◽  
Firing Shrinkage

Fly ash is an aluminosilicate and the major by-product from coal combustion in power stations; its increasing volumes are major economic and environmental concerns, particularly since it is one of the largest mineral resources based on current estimates. Mullite (3Al2O3·2SiO2) is the only stable phase in the Al2O3-SiO2 system and is used in numerous applications owing to its high-temperature chemical and mechanical stabilities. Hence, fly ash offers a potential economical resource for mullite fabrication, which is confirmed by a review of the current literature. This review details the methodologies to utilise fly ash with different additives to fabricate what are described as porous interconnected mullite skeletons or dense mullite bodies of approximately stoichiometric compositions. However, studies of pure fly ash examined only high-Al2O3 forms and none of these works reported long-term, high-temperature, firing shrinkage data for these mullite bodies. In the present work, high-SiO2 fly ashes were used to fabricate percolated mullite, which is demonstrated by the absence of firing shrinkage upon long-term high-temperature soaking. The major glass component of the fly ash provides viscosities suitably high for shape retention but low enough for ionic diffusion and the minor mullite component provides the nucleating agent to grow mullite needles into a direct-bonded, single-crystal, continuous, needle network that prevents high-temperature deformation and isolates the residual glass in the triple points. These attributes confer outstanding long-term dimensional stability at temperatures exceeding 1500 °C, which is unprecedented for mullite-based compositions.

Constitutive Analysis of the High-Temperature Deformation Behavior of Single Phase α-Ti and α+β Ti-6Al-4V Alloy

2007 ◽  
Vol 539-543 ◽  
pp. 3607-3612 ◽  
Author(s):  
Jeoung Han Kim ◽  
Jong Taek Yeom ◽  
Nho Kwang Park ◽  
Chong Soo Lee
Keyword(s):  
High Temperature ◽  
Flow Stress ◽  
Deformation Behavior ◽  
Single Phase ◽  
Volume Fraction ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Β Phase ◽  
Α Phase ◽  
Self Consistent

The high-temperature deformation behavior of the single-phase α (Ti-7.0Al-1.5V) and α + β (Ti-6Al-4V) alloy were determined and compared within the framework of self-consistent scheme at various temperature ranges. For this purpose, isothermal hot compression tests were conducted at temperatures between 650°C ~ 950°C to determine the effect of α/β phase volume fraction on average flow stress under hot-working condition. The flow behavior of α phase was estimated from the compression test results of single-phase α alloy whose chemical composition is close to that of α phase of Ti-6Al-4V alloy. On the other hand, the flow stress of β phase in Ti-6Al-4V was predicted by using self-consistent method. The flow stress of α phase was higher than that of β phase above 750°C, while the β phase revealed higher flow stress than α phase at 650°C. Also, at temperature above 750°C, the predicted strain rate of β phase was higher than that of α phase. It was found that the relative strength between α and β phase significantly varied with temperature.

High Temperature Deformation Behavior of Beta-Gamma TiAl Alloy

2007 ◽  
Vol 539-543 ◽  
pp. 1531-1536 ◽  
Author(s):  
J.S. Kim ◽  
You Hwan Lee ◽  
Young Won Kim ◽  
Chong Soo Lee
Keyword(s):  
High Temperature ◽  
Deformation Behavior ◽  
Tial Alloy ◽  
Microstructural Analysis ◽  
Processing Condition ◽  
Simulation Method ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Β Phase ◽  
Dynamic Materials

In this study, high-temperature deformation behavior of newly developed beta-gamma TiAl alloys was investigated in the context of the dynamic-materials model (DMM). Processing maps representing the efficiency of power consumption for microstructure evolution were constructed utilizing the results of compression test at temperatures ranging from 1000oC to 1200oC and strain rates ranging from 10-4/s to 102/s and Artificial Neural Network simulation method. With the help of processing map and microstructural analysis, the optimum processing condition for the betagamma TiAl alloy was investigated. The role of β phase was also discussed in this study.

Effect of Strain and Strain Rate on the Evolution of Dispersoid Particles in Al-Mn-Fe-Si Alloy during Hot Deformation

2013 ◽  
Vol 765 ◽  
pp. 398-402
Author(s):  
Thomas Hill ◽  
Joseph Robson ◽  
Nicolas Kamp
Keyword(s):  
Strain Rate ◽  
High Strain ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Constituent Particle ◽  
Strain And Strain Rate ◽  
High Strain Rate Deformation ◽  
Sem Imaging ◽  
Kinetics Of ◽  
Different Levels

The development of both dispersoid and constituent particle types during high temperature deformation has been investigated. Using torsion testing, which enables good temperature and strain rate control, the development of particles in terms of individual properties and the overall population has been examined during extended high strain rate deformation. Torsion tests also allow material that has the same thermal history but different levels of strain within a single sample to be compared. Quantitative comparison of particles has been performed using high resolution SEM imaging. Strain has been shown to have an important influence on particle evolution, beyond changing the kinetics of particle evolution alone. It has been demonstrated that the shape of the dispersoids is altered when they are evolving under the action of strain compared to that obtained from a thermal effect.

scholarly journals Using the Instrumented Indentation Technique to Determine Damage in Sintered Metal Matrix Composites after High-Temperature Deformation

2021 ◽  
Vol 11 (22) ◽  
pp. 10590
Author(s):  
Alexander Smirnov ◽  
Evgeniya Smirnova ◽  
Anatoly Konovalov ◽  
Vladislav Kanakin
Keyword(s):  
High Temperature ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Matrix Composites ◽  
Alloy Matrix ◽  
Plastic Properties ◽  
Sintered Metal ◽  
7075 Alloy

The paper shows the applicability of data on the evolution of the elastic modulus measured by the instrumented microindentation technique to the determination of accumulated damage in metal matrix composites (MMCs) under high temperature deformation. A composite with a V95 aluminum alloy matrix (the Russian equivalent of the 7075 alloy) and SiC reinforcing particles is used as the research material. The metal matrix composite was produced by powder technology. The obtained results show that, under macroscopic compression at temperatures ranging between 300 and 500 °C, the V95\10% SiC MMC has the best plasticity at 300 °C. At a deformation temperature of 500 °C, the plastic properties are significantly lower than those at 300 and 400 °C.

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