scholarly journals Further Research on Hardenability of Ti-1023 β Alloy Leading to a New DOE

2020 ◽  
Vol 321 ◽  
pp. 12032
Author(s):  
Bohumil Prazak
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Martensitic Transformation ◽  
Volume Fraction ◽  
Nucleation Mechanism ◽  
Alpha Particles ◽  
Primary Alpha ◽  
Trade Off ◽  
Nucleation Mechanisms

As part of a treatise on the hardenability of Ti-1023, a summary about the nucleation mechanisms of primary and secondary alpha, the viability of two-step aging, and existence of precipitation-free zones is provided. Assumptions are given on the nucleation mechanism of primary alpha particles and the effect of higher beta stabiliser content on stress-induced martensitic transformation. It is reminded that further research into two-step aging would be beneficial. A proposed design of the experiment deals with the existence of martensite in stressed samples, so that the martensitic transformation is minimized by an increased content of beta stabilisers, volume fraction of primary alpha, and beta grain size. Finally, a microstructure with stress-induced omega particles as precursors of secondary alpha particles may result in a better trade-off of mechanical properties; it is suggested that this be explored.

scholarly journals Grain Size Effect of the γ Phase Precipitation on Martensitic Transformation and Mechanical Properties of Ni–Mn–Sn–Fe Heusler Alloys

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2339
Author(s):  
Jinpei Guo ◽  
Minting Zhong ◽  
Wei Zhou ◽  
Yajiu Zhang ◽  
Zhigang Wu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Martensitic Transformation ◽  
Annealing Time ◽  
Volume Fraction ◽  
Heusler Alloys ◽  
Coarse Grained ◽  
Dual Phase ◽  
Average Grain Size ◽  
Stress Hysteresis

Isothermal annealing of a eutectic dual phase Ni–Mn–Sn–Fe alloy was carried out to encourage grain growth and investigate the effects of grain size of the γ phase on the martensitic transformation behaviour and mechanical properties of the alloy. It is found that with the increase of the annealing time, the grain size and volume fraction of the γ phase both increased with the annealing time predominantly by the inter-diffusion of Fe and Sn elements between the γ phase and the Heusler matrix. The isothermal anneals resulted in the decrease of the e/a ratio and suppression of the martensitic transformation of the matrix phase. The fine γ phase microstructure with an average grain size of 0.31 μm showed higher fracture strength and ductility values by 28% and 77% compared to the coarse-grained counterpart with an average grain size of 3.31 μm. The fine dual phase microstructure shows a quasi-linear superelasticity of 4.2% and very small stress hysteresis during cyclic loading, while the coarse dual phase counterpart presents degraded superelasticity of 2.6% and large stress hysteresis. These findings indicate that grain size refinement of the γ phase is an effective approach in improving the mechanical and transformation properties of dual phase Heusler alloys.

Effects of Pulsed Magnetic Field on the Microstructure and Mechanical Properties of Mg97Y2Zn1 Alloy

2014 ◽  
Vol 1004-1005 ◽  
pp. 123-126 ◽  
Author(s):  
Jian Yin ◽  
Xiu Jun Ma ◽  
Jun Ping Yao ◽  
Zhi Jian Zhou
Keyword(s):  
Magnetic Field ◽  
Mechanical Properties ◽  
Grain Size ◽  
Volume Fraction ◽  
Pulsed Magnetic Field ◽  
Second Phase ◽  
Microstructure And Mechanical Properties ◽  
Magnetic Field Treatment ◽  
Semi Solid ◽  
Strength And Plasticity

Effect of pulsed magnetic field treatment on the microstructure and mechanical properties of Mg97Y2Zn1 alloy has been investigated. When the pulsed magnetic field is applied on the alloy in semi-solid state, the α-Mg was modified from developed dendrite to fine rosette, resulting in a refined solidification microstructure with the grain size decreased from 4 mm to 0.5 mm. The volume fraction of the second phase ( X phase) increased by about 10 %. The yield strength, fracture strength and plasticity were improved by 21 MPa, 38 MPa and 2.4 %, respectively. The improvement of mechanical properties was attributed to the refined grain size and increased volume fraction of X phase.

The Influence of the Ferrite and Pearlite Grain Size on the S-N Fatigue Characteristics of Steel

2014 ◽  
Vol 224 ◽  
pp. 3-8 ◽  
Author(s):  
Sebastian Kamiński ◽  
Marcel Szymaniec ◽  
Tadeusz Łagoda
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Volume Fraction ◽  
Fatigue Properties ◽  
Phase Volume ◽  
Bending Tests ◽  
Phase Volume Fraction ◽  
Similar Chemical ◽  
Fatigue Characteristics ◽  
Ferrite Grain Size

In this work an investigation of internal structure influence on mechanical and fatigue properties of ferritic-pearlitic steels is shown. Ferrite grain size and phase volume fraction of three grades of structural steel with similar chemical composition, but different mechanical properties, were examined. Afterwards, samples of the materials were subjected to cyclic bending tests. The results and conclusions are presented in this paper

scholarly journals Microstructure, and Mechanical and Wear Properties of Grp/AZ91 Magnesium Matrix Composites

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1190 ◽  
Author(s):  
Chang-rui Wang ◽  
Kun-kun Deng ◽  
Yan Bai
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Yield Strength ◽  
Wear Mechanism ◽  
Thermal Deformation ◽  
Volume Fraction ◽  
Az91 Alloy

Based on semi-solid mixing technology, two kinds of as-cast Grp (Graphite particles)/AZ91 composites with different Grp volume fractions (5 vol %, 10 vol %) were prepared; these are called 5 vol % Grp/AZ91 composites and 10 vol % Grp/AZ91 composites, respectively. In order to eliminate casting defects, refine grains, and improve mechanical properties, thermal deformation analysis of these composites was conducted. The effect of the addition of Grp and thermal deformation on the microstructure, mechanical properties, and wear resistance of AZ91 composite was explored. The results showed that after 5 vol % Grp was added into the as-cast AZ91 alloy, Mg17Al12 phases were no longer precipitated reticularly along the grain boundary, and Al4C3 phases were formed inside the composite. With the increase in the volume fraction of Grp, the grains of the AZ91 composites were steadily refined. With the increase of forging pass, the grain size of 5% Grp/AZ91 composites decreased first, and then increased. Additionally, the Grp size decreased gradually. There was little change in the yield strength, and the tensile strength and elongation were improved to a certain extent. After forging and extrusion of 5% Grp/AZ91 composites once, the grain size and Grp size were further reduced, and the yield strength, tensile strength, and elongation were increased by 23%, 30%, and 65%, respectively, compared with the composite after forging. With the increase of the number of forging passes before extrusion, the grain size decreased little by little, while the Grp size remained unchanged. The average yield strength, tensile strength, and elongation of the composites after forging and extrusion six times were increased by 3%, 3%, and 23%, respectively, compared with the composite after forging and extrusion once. The wear rate and friction coefficient of the 5% Grp/AZ91 composites decreased after forging once, and the wear mechanism was mainly due to ploughing wear. By comparison, the wear rate and friction coefficient of the 5% Grp/AZ91 composites increased in the extrusion state, and the main wear mechanism was from wedge formation and micro-cutting wear.

scholarly journals Enhanced Mechanical Properties of Mg-6Sn-3Al-1Zn Alloy with Bimodal Grain Size Disturbed in the Microstructure Uniformly through Changing the Rolling Temperature

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Fuan Wei ◽  
Jinhui Wang ◽  
Ping Li ◽  
Bo Shi
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Yield Strength ◽  
Volume Fraction ◽  
Rolling Temperature ◽  
Average Grain Size ◽  
Small Grains ◽  
Mg2sn Phase ◽  
Average Size ◽  
Bimodal Grain Size

The mechanical properties of Mg-6Sn-3Al-1Zn alloy were enhanced with bimodal grain size disturbed in the microstructure uniformly; the Mg-6Sn-3Al-1Zn alloys were rolled with 60% thickness reduction at different rolling temperatures. The results have shown that the Mg-6Sn-3Al-1Zn alloys are composed of Mg2Sn phase and α-Mg matrix phase. When the rolling temperature was less than or equal to 400°C, with the rolling temperature increasing, the average size and volume fraction of Mg2Sn phase and the average grain size of small grains remained unchanged, the average grain size of large grains decreased, the volume fraction of small grains increased, and the yield strength of the alloy increased. When the rolling temperature reached 450°C, the average size and volume fraction of Mg2Sn phase and the average grain size of large grains increased, and the volume fraction of small grains and the yield strength of the alloy decreased. The elongation increased with the rolling temperature increasing, but the change trend of hardness was just opposite. When the alloy was rolled at 400°C, the average sizes of small grains, large grains, and Mg2Sn phases were 3.66 μm, 9.24 μm, and 19.5 μm, respectively. The volume fractions of small grains, large grains, and Mg2Sn phases were 18.6%, 77.6%, and 3.8%, respectively. And the tensile properties reached the optimum; for example, the tensile strength, yield strength, elongation, and Vickers hardness were 361 MPa, 289.5 MPa, 20.5%, and 76.3 HV, respectively.

Research on the Microstructures and Mechanical Properties of Annealed Cold Upsetting AZ31 Magnesium Alloy

2009 ◽  
Vol 610-613 ◽  
pp. 826-830
Author(s):  
Tian Mo Liu ◽  
Wei Hui Hu ◽  
Qing Liu
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Annealing Temperature ◽  
Volume Fraction ◽  
Cold Upsetting ◽  
Cast Magnesium Alloys ◽  
Microstructures And Mechanical Properties ◽  
Cast Magnesium

The microstructures and mechanical properties of cold upsetting magnesium alloys were investigated upon anneal under different conditions. The results show that a large amount of twins were observed in the original grains of cold upsetting AZ31 magnesium alloys. The twins disappeared gradually and recrystal grains formed after anneal. The volume fraction of the recrystal grains increases as the strain of samples rises. Recrystal grain size grows large with the elevated annealing temperature. Recrystal grain size reduces at first and then grows as the annealing time is prolonged. In addition, compared with as-cast magnesium alloys, the yield strength of cold upsetting samples increase apparently due to grain refinement after anneals.

Mechanical Properties of Diamond Fibres

1995 ◽  
Vol 383 ◽  
Author(s):  
N. M. Everitt ◽  
R. A. Shatwell ◽  
E. Kalaugher ◽  
E. Nicholson
Keyword(s):  
Mechanical Properties ◽  
Silicon Carbide ◽  
Grain Size ◽  
Fracture Strength ◽  
Coating Thickness ◽  
Tensile Testing ◽  
Volume Fraction ◽  
Thick Films ◽  
Diamond Coating ◽  
Bending Tests

ABSTRACTTungsten and silicon carbide fibres have been coated with diamond using the HFCVD technique. The diamond volume fraction varied between 26% and 73%. Resonance in bending tests gave a Young's modulus of 880 GPa for the diamond coating. Tensile testing indicated that the diamond fracture strength was between 600 MPa and 2000 MPa, depending on the coating thickness, and thus the grain size, of the diamond. The strain to failure of the diamond coating in bending was approximately 0.15% for 25 μm thick films.

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