Effect of Al, Cr, Mo, Zr, Si, and C on the temperature ranges of hardening of multicomponent niobium-based alloys

2020 ◽  
Vol 2020 (01) ◽  
pp. 67-76
Author(s):  
M. P. Brodnikovskyy ◽  
◽  
A. S. Kulakov ◽  
M. O. Krapivka ◽  
U. E. Zubets ◽  
...  

The effect of alloying and the strain rate on the occurrence and features of the manifestation of temperature ranges in which the strengthening of niobium alloys doped with Ti, Al, Cr, Mo, Zr, Si, C occurs was studied. It was found that in multicomponent solid solutions based on niobium up to sufficiently high temperatures more efficient hardening is provided than in precipitation hardened carbide alloys. It is shown that in multicomponent niobium alloys, which are a solid solution, the selection of alloying can be used to control the manifestation of a high-temperature hardening peak in a wide range. It is possible to change the temperature range of the peak manifestation, its height, sensitivity to the strain rate. The appearance of a high-temperature hardening peak is explained by the loss of stability of the multicomponent solid solution upon deformation in the dislocation field, which leads to the precipitation of dispersed particles of the second phase that pin the dislocations. Keywords: multicomponent niobium alloys, structure, temperature dependence of strength.

2011 ◽  
Vol 311-313 ◽  
pp. 583-586
Author(s):  
Xiu Zhi Zhang ◽  
Ying Jie Li ◽  
Yi Shuai Zhang

In this paper, the effect of heat treatment and strain rate on the tensile property of extruding magnesium alloys 1Mn1Zn4Y is studied by using tensile tests. It can be concluded that because the grain size of the sample with solid solution (T4) is coarser than that of the sample without heat treatment,the elongation and the strength of the specimen treated with solid solution are lower. However, owing to many fine and dispersed particles of the second phase precipitated from the solid solution, the strength of sample treated with solid solution + aging (T6) is the highest.


Author(s):  
A. H. Shafieizad ◽  
A. Zarei-Hanzaki ◽  
M. Ghambari ◽  
A. Abbasi-Bani

The present work deals with the high temperature flow behavior and the microstructure of the Al-Cu/Mg2Si metal matrix composite. Toward this end, a set of hot compression tests was performed in a wide range of temperature (573–773 K) and strain rate (0.001–0.1 s−1). The results indicated that the temperature and strain rate have a significant effect on the flow softening and hardening behavior of the material. The work hardening rate may be offset due to the occurrence of the restoration processes, the dynamic coarsening, and spheroidization of the second phase particles. In this regard, two phenomenological constitutive models, Johnson–Cook (JC) and Arrhenius-type equations, were employed to describe the high temperature deformation behavior of the composite. The JC equation diverged from experimental curves mainly in conditions which are far from its reference temperature and reference strain rate. This was justified considering the fact that JC model considers thermal softening, strain rate hardening, and strain hardening as three independent phenomena. In contrast, the Arrhenius-type model was more accurate in modeling of the flow behavior in wide range of temperature and strain rate. The minor deviation at some specified conditions was attributed to the negative strain rate sensitivity of the alloys at low temperature deformation regime.


2020 ◽  
Vol 6 (3) ◽  
pp. 113-123
Author(s):  
Arnold S. Borukhovich

The results of the creation of a high-temperature spin injector based on EuO: Fe composite material are discussed. Their magnetic, electrical, structural and resonance parameters are given in a wide range of temperatures and an external magnetic field. A model calculation of the electronic spectrum of the solid solution Eu–Fe–O, responsible for the manifestation of the outstanding properties of the composite, is performed. The possibility of creating semiconductor spin electronics devices capable of operating at room temperature is shown.


2014 ◽  
Vol 783-786 ◽  
pp. 1129-1135
Author(s):  
Takehito Hagisawa ◽  
Hirokazu Madarame ◽  
Shinji Tanaka ◽  
Yasuyuki Kaneno ◽  
Takayuki Takasugi

High temperature compression properties of Al-, Cr-or Nb-added Ni3(Si,Ti) based intermetallic compounds were investigated by uni-axial compression test and microstructural observation. The Al-or Cr-added Ni3(Si,Ti) alloys after homogenization heat treatment exhibited a two-phase microstructure consisting of L12and Ni-solid solution phases. The Nb-added Ni3(Si,Ti) alloy after homogenization heat treatment exhibited a triple-phase microstructure consisting of G-phase with D8a structure and Ni-solid solution phase in the L12matrix. The volume fraction of Ni-solid solution phase increased in order of Cr-, Nb-and Al-added Ni3(Si,Ti) alloys. The Cr-added Ni3(Si,Ti) alloy was deformable at high strain rate, while the Nb-added one was deformable at low strain rate. It can be considered that the deformability of Ni3(Si,Ti) at high temperature is closely correlated with volume fraction of Ni-solid solution phase and recrystallization behavior.


1996 ◽  
Vol 11 (6) ◽  
pp. 1433-1439 ◽  
Author(s):  
Anne Vilette ◽  
S. L. Kampe

Cubic (δ) bismuth oxide (Bi2O3) has been subjected to high temperature deformation over a wide range of temperatures and strain rates. Results indicate that bismuth oxide is essentially incapable of plastic deformation at temperatures below the monoclithic to cubic phase transformation which occurs at approximately 730 °C. Above the transformation temperature, however, Bi2O3 is extensively deformable. The variability of flow stress to temperature and strain rate has been quantified through the determination of phenomenological-based constitutive equations to describe its behavior at these high temperatures. Analysis of the so-determined deformation constants indicate an extremely strong sensitivity to strain rate and temperature, with values of the strain-rate sensitivity approaching values commonly cited as indicative of superplastic behavior.


2016 ◽  
Vol 849 ◽  
pp. 162-167
Author(s):  
Geng Hua Cao ◽  
Da Tong Zhang

Cast Mg-4.27Y-2.94Nd-0.51Zr (wt.%) alloy was subjected to submerged friction stir processing (SFSP) with at a rotation rate of 600 rpm and a traveling speed of 60 mm min-1. Superplastic behavior of specimens with an average grain size of ~1.3 μm were investigated in the temperature ranges of 683-758 K and the strain rate ranges from 1×10-1 to 4×10-4 s-1. Microstructure characteristics were investigated by optical microscopy, scanning electron microscopy and transmission electron microscopy. The results show that the maximum elongation of 967% was obtained at 733 K and 3×10-3 s-1, the optimal HSRS of 900% achieved at 758 K and 2×10-2 s-1. Grains and second phase particles grew coarser with the increasing temperature or decreasing strain rate. Remarkable grain growth is the main reason that elongations are all significantly decreased when the strain rate decrease from 3×10-3 s-1 to 4×10-4 s-1. Grain boundary sliding is the main mechanism during superplastic deformation.


2021 ◽  
Author(s):  
Pradeep Lall ◽  
Vishal Mehta ◽  
Jeff Suhling ◽  
Ken Blecker

Abstract Electronic parts may often get exposed to high strains during shocks, vibrations and drop conditions in both commercial and defense applications. In addition, such electronic parts can often be simultaneously exposed to extreme surrounding temperatures between −65°C and 200°C after storage in non-climate-controlled conditions. Electronic equipment can be subjected to strain rates of 1 to 100 per second in shock and vibration. Many of the doped SAC soldering alloys in the electronic components, including SAC-Q, SAC-R, Innolot have found applications in long-term thermal exposure environments. Low temperature high strain-rate properties are needed to assure durability under high temperature storage followed by shock and vibration. There is scarcity of high strain-rate data on alloys exposed to high temperature aging operating at extreme low-temperatures and extremely-high temperatures. For this study, SAC-Q material was tested and analyzed at temperatures from −65°C to 200°C and at a strain rates of from 10 to 75 per second. Following the production and retrieval of the specimens, specimens were stored for isothermal aging for up to 6 months at 100°C temperature, before performing tensile test experiments at various operating temperatures. Stress vs strain curves are formed for the wide range of strain rates and surrounding temperatures. In addition, test results and data were complemented by the Anand viscoplasticity model and by calculating stress-strain behavior, evaluated in a wide range of working temperatures and strains rates.


2005 ◽  
Vol 495-497 ◽  
pp. 579-584 ◽  
Author(s):  
Kazuto Okayasu ◽  
Hiroshi Fukutomi

Uniaxial compression tests were conducted on Al-3mass%Mg alloy under various temperatures and strain rates. High temperature yielding was observed at the temperatures higher than 623K. Texture examination elucidated that fiber textures are constructed in all the deformation conditions examined in this study. It was found that the kinds and intensities of texture components varied depending on deformation temperature, strain rate and the amount of strain.


Coatings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1444
Author(s):  
Haobo Mao ◽  
Fuqiang Shen ◽  
Yingyi Zhang ◽  
Jie Wang ◽  
Kunkun Cui ◽  
...  

TiC ceramics have become one of the most potential ultra-high temperature structural materials, because of its high melting point, low density, and low price. However, the poor mechanical properties seriously limit its development and application. In this work, this review follows PRISMA standards, the mechanism of the second phase (particles, whiskers, and carbon nanotubes) reinforced TiC ceramics was reviewed. In addition, the effects of the second phase on the microstructure, phase composition and mechanical properties of TiC ceramics were systematically studied. The addition of carbon black effectively eliminates the residual TiO2 in the matrix, and the bending strength of the matrix is effectively improved by the strengthening bond formed between TiC; SiC particles effectively inhibit the grain growth through pinning, the obvious crack deflection phenomenon is found in the micrograph; The smaller grain size of WC plays a dispersion strengthening role in the matrix and makes the matrix uniformly refined, and the addition of WC forms (Ti, W) C solid solution, WC has a solid solution strengthening effect on the matrix; SiC whiskers effectively improve the fracture toughness of the matrix through bridging and pulling out, the microscopic diagram and mechanism diagram of SiC whisker action process are shown in this paper. The effect of new material carbon nanotubes on the matrix is also discussed; the bridging effect of CNTs can effectively improve the strength of the matrix, during sintering, some CNTs were partially expanded into GNR, in the process of crack bridging and propagation, more fracture energy is consumed by flake GNR. Finally, the existing problems of TiC-based composites are pointed out, and the future development direction is prospected.


2011 ◽  
Vol 1298 ◽  
Author(s):  
David G. Morris ◽  
Maria Antonia Muñoz-Morris

ABSTRACTProcesses of severe plastic deformation have been investigated for a wide range of ductile alloys over the past decade, generally with an objective of refining the microstructural scale, for example the grain size, but have hardly been considered for intermetallics. This presentation discusses processing of a boride-containing Fe3Al alloy using a multidirectional, high-strain and high-temperature forging technique. Iron aluminides with relatively low Al contents can be regarded as Al-rich ferritic steels with outstanding oxidation-corrosion properties. However, as for many ferritic steels, they show poor creep resistance at temperatures above about 600ºC. The deformation processing leads to a material with large grain size and refined dispersion of thermally-stable boride particles. The particles produce a large increase in creep strength under conditions of moderate stresses and low strain rates at temperatures near 700ºC. This high-strain forging technique can be seen as an intermediate processing method between conventional wrought metallurgy and mechanical-alloying powder metallurgy, whereby an initially coarse and inhomogeneous dispersion of second phase is refined and made more homogeneous, and can be considered as a useful processing technique for a wide range of particle-containing materials.


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