On the Correlation of the Hardness of B2 Compounds with Point Defect Concentrations

1994 ◽  
Vol 364 ◽  
Author(s):  
L. M. Pike ◽  
Y. A. Chang ◽  
C. T. Liu
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Point Defect ◽  
Point Defects ◽  
Defect Structure ◽  
Experimental Methods ◽  
Structure Defect ◽  
Quenching Temperature ◽  
Solid Solution Strengthening ◽  
Solution Strengthening

AbstractPoint defects such as vacancies and anti-site atoms are known to strongly affect the mechanical properties of B2 compounds. The variations in the hardness of these compounds with composition and quenching temperature can often be correlated with the concentrations of these point defects. Simple themodynamic models using a quasi-chemical approach can be used to estimate the concentrations of point defects with composition and temperature. These estimates can often be supported by experimental methods. Knowledge of the concentrations of defects can then be compared to the variations in hardness using solid solution strengthening models. A consistent relationship is found for several B2 compounds. The hardening rates of vacancies are found to be greater than those of anti-site atoms. B2 compounds having the anti-structure defect structure (AuZn, FeCo) are investigated as well as those with the triple-defect structure (FeAl, NiAl, CoAl).

Effect of Ti Element on Microstructure and Properties of Cu-Cr Alloy

2015 ◽  
Vol 817 ◽  
pp. 307-311 ◽  
Author(s):  
Peng Chao Zhang ◽  
Jin Chuan Jie ◽  
Yuan Gao ◽  
Tong Min Wang ◽  
Ting Ju Li
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Spherical Shape ◽  
Precipitation Strengthening ◽  
Peak Hardness ◽  
Ti Alloy ◽  
Strengthening Mechanisms ◽  
Vacuum Melting ◽  
Solid Solution Strengthening ◽  
Solution Strengthening

The Cu-Cr and Cu-Cr-Ti alloy plates were prepared by vacuum melting and plastic deformation. The effect of slight Ti element on microstructure and mechanical properties of Cu-Cr alloy was discussed. The result shows that Cr particles with spherical shape precipitated from Cu matrix after aging. Plenty Ti atoms dissolved in the vicinity of Cr particles and there were still parts of solid solution Ti atoms in other regions. Improvements in peak hardness and softening resistance were achieved with the addition of Ti element in Cu-Cr alloy. The addition of 0.1 wt.% Ti element makes Cu-Cr alloy possess tensile strength of 565 MPa and hardness of 185.9 HV after aging at 450 °C for 120 min, which can be attributed to multiple strengthening mechanisms, i.e. work hardening, solid solution strengthening and precipitation strengthening.

Pseudoelasticity in High Strengthening Fcc Single Crystals

1996 ◽  
Vol 459 ◽  
Author(s):  
Yu.I. Chumlyakov ◽  
I. V. Kireeva ◽  
G. S. Kapasova ◽  
E. I. Litvinova
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Single Crystals ◽  
Stress Level ◽  
Deformation Mechanism ◽  
Crystal Orientation ◽  
Dispersion Hardening ◽  
Solid Solution Strengthening ◽  
Solution Strengthening ◽  
Applied Stresses

ABSTRACTIt was experimentally shown that the achievement of a high deforming stress level due to dispersion hardening and solid solution strengthening of FCC single crystals with a low stacking-fault energy leads to the deformation mechanism changing from slip to twinning, the dependence of mechanical properties on a crystal orientation and a sign of applied stresses. During deformation by twinning at T<150–300K effects of pseudoelasticity associated with elastic twinning is observed.

Mechanical Properties of Ga1–xInxAs

1985 ◽  
Vol 53 ◽  
Author(s):  
S. Guruswamy ◽  
J.P. Hirth ◽  
K.T. Faber
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
High Temperature ◽  
Strengthening Effect ◽  
Plateau Stress ◽  
Solid Solution Strengthening ◽  
Stress Region ◽  
Solution Strengthening ◽  
Concentration Levels ◽  
Undoped Gaas

ABSTRACTSubstantial solid solution strengthening of GaAs by In acting as InAs4 units has recently been predicted. This strengthening could account for the reduction of dislocation density in GaAs single crystals grown from the melt. High temperature hardness measurements up to 700ºC have been carried out on (100) GaAs and Ga0.9975 In0.0025 As wafers. Results show a significant strengthening effect in In—doped GaAs even at concentration levels of about 0.2 wt%. A temperature independent flow stress region is observed for both these alloys. The In—doped GaAs shows ahigher plateau stress level compared to the undoped GaAs. The results are consistent with the solid solution strengthening model.

The Effect of Heat Treatment on Microstructure and Mechanical Properties of ZK60 Alloy

2007 ◽  
Vol 353-358 ◽  
pp. 718-721
Author(s):  
Ding Fei Zhang ◽  
Rong Shen Liu ◽  
Jian Peng ◽  
Wei Yuang ◽  
Hong Ju Zhang
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Solid Solution ◽  
Age Hardening ◽  
Second Phase ◽  
Solid Solution Strengthening ◽  
Microstructure And Mechanical Properties ◽  
Long Time ◽  
Zk60 Alloy ◽  
Solution Strengthening

With different heat treatment, the microstructure and mechanical properties of ZK60 magnesium alloy were investigated. It can be concluded that heat treatment has great effect on mechanical properties of ZK60. With artificial aging after extruding, the precipitation of the second phase from the supersaturated solid solution significantly improved mechanical properties. It can greatly increase yield strength of ZK60 alloy, while the tensile strength has little change. For the combination of solid solution strengthening and age hardening, two opposite factors must be considered. On one hand, the solid solution strengthening and the later precipitation strengthening is good for alloy’s strength; on the other hand, the properties decrease as the grains grew under high temperature for a long time during solution heating.

Hardening by Point Defects and Solutes in B2 Intermetallics

2002 ◽  
Vol 753 ◽  
Author(s):  
L. M. Pike ◽  
Y. A. Chang ◽  
C. T. Liu ◽  
I. M. Anderson
Keyword(s):  
Solid Solution ◽  
Point Defect ◽  
Point Defects ◽  
Solid Solution Hardening ◽  
Quenching Temperature ◽  
Solid Solution Softening ◽  
Ordered Intermetallic ◽  
Multiple Defect ◽  
Binary Compounds ◽  
Hardness Values

ABSTRACTThis paper provides a review of recent progress on point defect and solute hardening in binary and ternary B2 intermetallics. As is the case for disordered metallic solutions, the presence of point defects and solute atoms in ordered intermetallic compounds results in solid solution hardening (SSH). However, factors unique to ordered systems are often responsible for unusual hardening effects. Binary compounds with identical crystal structures can exhibit significantly different hardness behavior. Ternary solute additions to ordered compounds can give rise to apparent solid solution softening as well as unexpectedly rapid hardening. These effects arise from the interaction of multiple defect types as well as the presence of multiple sublattice sites available for solute occupation. Therefore, before the SSH behavior of ordered intermetallics can be properly studied, it is necessary to develop an understanding of the types and quantities of the point defects which are present. Three recent studies by the authors are reviewed. Much of the work was done on NiAl and FeAl in binary form as well as with ternary additions. Defect concentrations over wide ranges in alloy composition and quenching temperature were determined using the ALCHEMI (atom location by channeling enhanced microanalysis) technique combined with vacancy measurements. Hardness values were also measured. It was found that most of the observed SSH effects could be rationalized on the basis of the measured point defect concentrations.

scholarly journals Plasma Facing Material by Self-Interstitial Solid Solution Strengthening – Problem, Proposition, and a Solution

2020 ◽  
Author(s):  
Muhammad Musaddique Ali Rafique
Keyword(s):  
Solid Solution ◽  
Crystal Lattice ◽  
Point Defect ◽  
Lattice Defect ◽  
Solid Solution Strengthening ◽  
Coordination Sites ◽  
Pair Generation ◽  
Solution Strengthening ◽  
Fcc Structure ◽  
Facing Material

Bubble (point defect) &ndash; a precursor of fuzz or under dense nanostructure formation is crystal lattice defect. Suitable selection of crystal lattice which inhibit Frenkel pair generation and intrinsically promotes selfinterstitial solid solution strengthening contributes effectively towards making plasma facing material. For this, interstitial sites, their size, amount / fraction, positions, tendency of occupation and diffusion parameters (e.g. activation energies (Q), activation volumes) are determined. Fcc iron carbon alloys (austenitic stainless steels AISI / SAE 321, fcc structure, Pearson code cF4, space group Fm3̅m) are proposed as suitable candidates. Along with their room temperature fcc structure having 12 interstitial positions (4 octahedral, 6 coordination sites and 8 tetrahedral, 4 coordination sites / unit cell) to allow insertion of self (iron) atoms, they have excellent corrosion resistance, thermal conductivity, and nonmagnetic properties. After their melting, casting, and machining to required dimensions and geometry, stabilizing heat treatment is applied to precipitate all carbon as TiC and prevent formation of Cr23C6 (sensitization). This resist heat and surface degradation and yield excellent architecture which not only inhibit Frankel pair generation but will also allow bulk assimilation or surface annihilation (loop punching) of this lattice point defect. A superior thermal, fluid, and structural design augment above

scholarly journals Orientation-dependent solid solution strengthening in zirconium: a nanoindentation study

2019 ◽  
Vol 55 (10) ◽  
pp. 4493-4503 ◽  
Author(s):  
Arijit Lodh ◽  
Prita Pant ◽  
Gulshan Kumar ◽  
K. V. Mani Krishna ◽  
Raghvendra Tewari ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Finite Element ◽  
Elastic Modulus ◽  
Constitutive Relationship ◽  
Insignificant Change ◽  
Solid Solution Strengthening ◽  
Pure Zirconium ◽  
Solution Strengthening ◽  
Peak Value

AbstractOrientation-dependent solid solution strengthening was explored through a combined microtexture plus nanoindentation study. Pure zirconium (6N purity crystal-bar Zr) and commercial Zircaloy-2 were investigated for comparison. Local mechanical properties were estimated through finite element (FE) simulations of the unloading part of the nanoindentation load–displacement response. Combinations of ‘averaging’ scheme and constitutive relationship were used to resolve uncertainty of FE-extracted mechanical properties. Comparing the two grades, non-basal oriented grains showed an overall hardening and increase in elastic modulus. In contrast, insignificant change was observed for basal (or near-basal) oriented grains. The strengthening of non-basal orientations appeared via elimination of the lowest hardness/stiffness values without a shift in the peak value. Such asymmetric development brought out the clear picture of orientation-dependent solid solution strengthening in zirconium.

Optical, Thermal, and Mechanical Properties of (Y1-xScx)2O3 Transparent Ceramics

2021 ◽  
Author(s):  
Jiquan Huang ◽  
Changliang YANG ◽  
Qiufeng HUANG ◽  
Zhonghua DENG ◽  
Yun WANG ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Transparent Ceramics ◽  
Sintering Process ◽  
Vacuum Sintering ◽  
Solid Solution Strengthening ◽  
Complete Solid Solution ◽  
Wide Wavelength Range ◽  
Universal Approach ◽  
Solution Strengthening

Abstract Sesquioxides such as Y2O3 and Sc2O3 are important optical materials, but the fabrication of their transparent ceramics remains a challenge due to the ultra-high melting point of over 2400 oC. In this work, a series of (Y1-xScx)2O3 transparent ceramics were successfully fabricated by a simple vacuum sintering process without any sintering additives, and the effect of Scandium (Sc) content on the crystal structure and optical/thermal/mechanical properties were evaluated. Y2O3 and Sc2O3 form a complete solid solution with a cubic bixbyite structure. The formation of (Y1-xScx)2O3 solid solution promotes the densification of ceramics, leading to the realization of high transparency close to the theoretical transmittance over a wide wavelength range of 0.35-8 mm. In particular, the in-line transmittance in the range of 0.6-6 mm remains above 80% for (Y1-xScx)2O3 with x = 0.23-0.31, while the pristine Y2O3 and Sc2O3 are opaque. Moreover, the mechanical properties including Vickers hardness (Hv), fracture toughness (KIC), and biaxial strength (δb) are evidently enhanced due to the solid solution strengthening, while the thermal conductivity is reduced due to the reduction of photon free path. This study demonstrates that forming of solid solution is a facile and universal approach for preparing sesquioxides transparent ceramics with high optical and mechanical quality.

Mechanical Properties and Microstructure of Strip Casted Ag-27%Cu-25%Zn-3%Sn Brazing Alloy

2007 ◽  
Vol 26-28 ◽  
pp. 485-488 ◽  
Author(s):  
Kee Ahn Lee ◽  
Sung Jun Kim ◽  
Moon Chul Kim
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Solid Solution ◽  
Microstructural Analysis ◽  
Mechanical Tests ◽  
Rich Phase ◽  
Aging Heat Treatment ◽  
Solid Solution Strengthening ◽  
Solution Strengthening ◽  
Twin Roll

This work sought to examine the suitability of twin roll strip casting for Ag-27%Cu- 25%Zn-3%Sn brazing alloy (BAg-7A) and to investigate the mechanical properties and microstructure of the strip. The effect of aging heat treatment on the properties was also studied. This new manufacturing process has applications in the production of the brazing alloy. XRD and microstructural analysis of the Ag-27%Cu-25%Zn-3%Sn strip represented eutectic microstructure of a Cu-rich phase and a Ag-rich matrix regardless of heat treatment. The results of mechanical tests showed tensile strength of 470MPa, a significant enhancement; and an 18% elongation of the twin roll casted strip, due mainly to the solid solution strengthening of Zn atoms (~20%) in the Cu-rich phases. Tensile results showed gradually decreasing strengths and increasing elongation with aging heat treatment. Microstructural evolution and fractography were also investigated and related to the mechanical properties.

Solid-Solution Strengthening Effect of Vanadium Addition to Iron-Modified L12 Titanium Trialuminides

1994 ◽  
Vol 364 ◽  
Author(s):  
Tohru Takahashi ◽  
Tadashi Hasegawa
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Intermetallic Compounds ◽  
Argon Atmosphere ◽  
Strengthening Effect ◽  
Cubic Symmetry ◽  
Solid Solution Strengthening ◽  
Arc Melting ◽  
Solution Strengthening ◽  
Cubic Structure

AbstractTwo types of aluminum–titanium–iron–vanadium ( Al–Ti–Fe–V ) quarternary intermetallic compounds have been prepared by arc melting under argon atmosphere. Their compositions were nominally Al66Ti25Fe6V3 and Al66Ti25Fe3V6. These alloys are based on the iron–modified titanium trialuminide with L12 cubic structure. Vanadium addition up to about 6 mol% did not destroy the cubic symmetry, and L12 solid solution compounds were produced in these two Al–Ti–Fe–V quarternary alloys. Microstructure and mechanical properties have been investigated. It has been demonstrated that vanadium addition to iron–modified L12 titanium trialuminides can enhance their strength.

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