Fracture Toughness of Nanocrystalline L12 (Al+X at.%Mn)3 Ti Prepared by Mechanical Alloying and Consolidated by SPS

AbstractThe effects of ternary element addition of manganese on microstructure and mechanical properties of nanocrystalline L12 (Al+X at.%Mn)3Ti (X=0 - 12) fabricated by mechanical alloying and spark plasma sintering (SPS) were investigated. The SPS method was used to consolidate nanocrystalline L12 (Al+X at.%Mn)3Ti with the pressure of 50 MPa. The heating rate was 100°C /min. The final sintering temperature was determined from the observation of the shrinkage of the specimen. In binary Al3Ti, the final sintering temperature was 864°C. The sintering temperature was reduced down to 658°C with increasing Mn concentration. After SPS, the L12 structure was maintained in the specimens which contained Mn concentration of 8- 12 at.%. The microhardness test, grain size measurements, and fracture toughness test were conducted as a function of Mn concentration. In order to investigate the effect of the grain size on the microhardness and fracture toughness of the (Al+8 at.%Mn)3Ti, heat treatments were performed in a vacuum furnace ( 10-3 torr ). With increasing heat treatment temperature, the microhardness decreased due to the formation and growth of Al4C3, Al2O3, and TiC, while fracture toughness increased. The fracture toughness of 4.12 MPa m1/2 was attained for the (Al+8 at.%Mn)3Ti specimen and it was the highest value among the specimens after 1h heat treatment at 1100°C. The grain sizes were about 60 nm and 100 nm after 1 h heat treatment at 900°C and 1100°C, respectively.

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Fatigue and Fracture of Engineering Alloys

10.31399/asm.tb.ffub.t53610209 ◽

2012 ◽

pp. 209-261

Keyword(s):

Heat Treatment ◽

Fracture Toughness ◽

Grain Size ◽

Corrosion Damage ◽

Operating Conditions ◽

Fracture Properties ◽

Fatigue And Fracture ◽

Engineering Alloys ◽

Accelerate Crack Growth ◽

Crack Growth Rates

Abstract This chapter provides information and data on the fatigue and fracture properties of steel, aluminum, and titanium alloys. It explains how microstructure, grain size, inclusions, and other factors affect the fracture toughness and fatigue life of these materials and the extent to which they can be optimized. It also discusses the effect of metalworking and heat treatment, the influence of loading and operating conditions, and factors such as corrosion damage that can accelerate crack growth rates.

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Effect of Heat-Treatment on the Thermal and Mechanical Stability of Ni/Al2O3 Nanocrystalline Coatings

Journal of Manufacturing and Materials Processing ◽

10.3390/jmmp4010017 ◽

2020 ◽

Vol 4 (1) ◽

pp. 17

Author(s):

Kavian O. Cooke ◽

Tahir I. Khan ◽

Muhammad Ali Shar

Keyword(s):

Heat Treatment ◽

Grain Size ◽

Mechanical Stability ◽

Chemical Properties ◽

Treatment Temperature ◽

Al2o3 Coating ◽

Operational Temperature ◽

Average Grain Size ◽

Properties Of Materials ◽

Physical And Chemical

Heat-treatment is a frequently used technique for modifying the physical and chemical properties of materials. In this study, the effect of heat-treatment on the mechanical properties, thermal stability and surface morphology of two types of electrodeposited coatings (pure-Ni and Ni/Al2O3) were investigated. The XRD analyses showed that the crystal structure of the as-deposited coating changes from slightly amorphous to crystalline as the heat-treatment temperature increases. The heat-treatment of both the pure-Ni and the Ni/Al2O3 coating caused an increase of the grain size within the coatings. However, the unreinforced Ni coating experienced a faster growth rate than the Ni/Al2O3 coating, which resulted in a larger average grain size. The temperature-driven changes to the microstructure of the coatings caused a reduction in the hardness and wear resistance of the coatings. The presence of nanoparticles within the Ni/Al2O3 coating can successfully extend the operational temperature range of the coating to 473 K by pinning grain boundaries.

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Solution Processed Bi-Based Sensitized Solar Cell: Effects of Post Heat Treatment

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2019.16099 ◽

2019 ◽

Vol 19 (6) ◽

pp. 3505-3510 ◽

Cited By ~ 1

Author(s):

Yik Chong Chai ◽

Hieng Kiat Jun

Keyword(s):

Heat Treatment ◽

Quantum Dots ◽

Solar Cell ◽

Heat Treatment Temperature ◽

Sintering Temperature ◽

Gradual Increase ◽

Treatment Temperature ◽

Post Heat Treatment ◽

Dipping Process ◽

Sensitized Solar Cells

Nanosize semiconductors have been used as active sensitizers for the application of quantum dot-sensitized solar cells (QDSSC). “Green” sensitizers are introduced as an alternative for the toxic Cd and Pb based compounds. In this work, Bi2S3 quantum dots (QDs) were fabricated and used as sensitizers in QDSSC. QDs were grown on TiO2 electrode via solution dipping process. Although the performance of “green” QDSSC is not as high as that of CdS or CdSe based QDSSCs, its performance can be enhanced with post heat treatment. The effect is dependent on the heat treatment temperature profile where gradual increase of sintering temperature is preferred. The effects of post heat treatment on Bi2S3 sensitized TiO2 electrodes are investigated and discussed.

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Effect of Heat Treatment Temperature on the Spinning Structure and Properties of a Cu–Sn Alloy

Microscopy and Microanalysis ◽

10.1017/s1431927619015101 ◽

2019 ◽

Vol 26 (1) ◽

pp. 29-35

Author(s):

Jinli Liu ◽

Wenyuan Zheng ◽

Huiqin Yin

Keyword(s):

Heat Treatment ◽

Grain Size ◽

Grain Boundary ◽

Heat Treatment Temperature ◽

Treatment Temperature ◽

Recrystallization Temperature ◽

Boundary Orientation ◽

Different Temperatures ◽

Alloy Microstructure ◽

Electron Back Scattered Diffraction

AbstractA thin-walled copper (Cu)–tin (Sn) alloy cylinder was treated after spinning at 200–400°C for 0.5 h. The characteristics of the alloy microstructure under different temperatures were analyzed through electron back-scattered diffraction. The results were as follows. The grain size at 200–300°C decreases as the heat treatment temperature rises, but the grain size at 400°C increases. At 200–300°C, the microstructure primarily consists of deformed grains. It is found that the main reason for the formation of high-angle grain boundaries (HAGBs) is static recrystallization. For the grain boundary orientation differential, the low-angle sub-grain boundary gradually grows into the HAGB, and multiple annealing twin Σ9 boundaries appear. Grain orientation is generally random at any temperature range. The mechanical property test indicated that, at the upper critical recrystallization temperature of 300°C, the elongation of the Cu–Sn alloy gradually increases, and its yield strength and ultimate tensile strength rapidly decrease.

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Microstructural Change during the Interrupted Quenching of the AlZnMg(Cu) Alloy AA7050

Materials ◽

10.3390/ma13112554 ◽

2020 ◽

Vol 13 (11) ◽

pp. 2554 ◽

Cited By ~ 1

Author(s):

Thomas M. Kremmer ◽

Phillip Dumitraschkewitz ◽

Daniel Pöschmann ◽

Thomas Ebner ◽

Peter J. Uggowitzer ◽

...

Keyword(s):

Heat Treatment ◽

Fracture Toughness ◽

Yield Strength ◽

Phase Distribution ◽

Atom Probe ◽

Industrial Applications ◽

Treatment Temperature ◽

Strength Increase ◽

Artificial Ageing ◽

Cu Alloy

This study reports on the effect of interrupted quenching on the microstructure and mechanical properties of plates made of the AlZnMg(Cu) alloy AA7050. Rapid cooling from the solution heat treatment temperature is interrupted at temperatures between 100 and 200 °C and continued with a very slow further cooling to room temperature. The final material’s condition is achieved without or with subsequent artificial ageing. The results show that an improvement in the strength–toughness trade-off can be obtained by using this method. Interrupted quenching at 125 °C with peak artificial ageing leads to a yield strength increase of 27 MPa (538 MPa to 565 MPa) compared to the reference material at the same fracture toughness level. A further special case is the complete omission of an artificial ageing treatment with interrupted quenching at 200 °C. This heat treatment exhibits an 20% increase in fracture toughness (35 to 42 MPa m−1/2) while retaining a sufficient yield strength of 512 MPa for industrial applications. A detailed characterization of the relevant microstructural parameters like present phases, phase distribution and precipitate-free zones is performed using transmission electron microscopy and atom probe tomography.

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Evolution and Evaluation of Duplex Grain of As-cast 30Cr2Ni4MoV Steel during Heat Treatment

Materials Science ◽

10.5755/j01.ms.26.3.22102 ◽

2020 ◽

Vol 26 (3) ◽

pp. 281-286

Author(s):

Xiuzhi ZHANG ◽

Zhilong LIU ◽

Jiansheng LIU ◽

Shue DANG

Keyword(s):

Heat Treatment ◽

Grain Size ◽

Isothermal Holding ◽

Optical Microscope ◽

Treatment Temperature ◽

Heating Process ◽

Isothermal Heat Treatment ◽

Austenite Grains ◽

Different Grain Size ◽

Heat Preservation

As the main microstructure flaw of heavy forging, duplex grain (the grain size is non-uniform) may result in producing a reject. In this paper, the influences of heat treatment temperature and isothermal holding time on the duplex grains evolutions of as-cast 30Cr2Ni4MoV steel were studied using optical microscope and scanning electron microscope aided with XRD and EDS. It is shown that the globular austenite grains appear at 750 °C and the austenite grains in the regions rich in C, Cr, Ni, and Mo are smaller than that in other regions. Duplex grains appear in the heating process. Moreover, in the isothermal heat treatment process, grains with different grain size number also developed at all of the temperatures performed in the study. But the distribution of the grains with different sizes cannot be evaluated precisely using proper method commonly used now. On the basis of analysis of the sizes of the duplex grains, a new approach for evaluating the level of the mixture of different size grains was proposed, the result obtained are consistent with the experimental results. The microstructure of 30Cr2Ni4MoV could be more uniform by increasing the temperature and extending the heat-preservation time.

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Synthesis of Bi4-xYbxTi3O12 Nanopowders by a Modified Sol-Gel Process

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.336-338.2002 ◽

2007 ◽

Vol 336-338 ◽

pp. 2002-2004

Author(s):

Xian Qun Chen ◽

Qiu Sun ◽

Hong Cheng Liu

Keyword(s):

Heat Treatment ◽

Grain Size ◽

Bismuth Titanate ◽

Sol Gel ◽

Treatment Temperature ◽

Phase Changes ◽

Nanocrystalline Powders ◽

Temperature Phase ◽

Cation Substitution ◽

Sol Gel Process

Rare earth Yb-doped bismuth titanate Bi4-xYbxTi3O12 (BYT) nanocrystalline powders were obtained by a modified sol-gel method. TG-DTA, FI-IR and XRD were used to determine the lowest heat treatment temperature. Phase changes in the formation of BYT crystalline powders were discussed by XRD. The effect of Yb3+ cation substitution for Bi3+ cation on the microstructure of BYT was also developed with XRD. The grain size of BYT nanopowders is about 40 nm determined by TEM.

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HEAT TREATMENT EFFECTS ON STRUCTURE AND PROPERTIES OF SYNTHESIZED NANOCRYSTALLINE NiTi INTERMETALLIC BY MECHANICAL ALLOYING

International Journal of Modern Physics B ◽

10.1142/s0217979208047821 ◽

2008 ◽

Vol 22 (18n19) ◽

pp. 2970-2978

Author(s):

T. MOUSAVI ◽

M. H. ABBASI ◽

F. KARIMZADEH ◽

M. H. ENAYATI

Keyword(s):

Heat Treatment ◽

Grain Size ◽

Mechanical Alloying ◽

Lattice Strain ◽

Metastable Phase ◽

Nanocrystalline Structure ◽

X Ray Diffraction ◽

Niti Phase ◽

High Microhardness ◽

The Right

NiTi intermetallic with nanocrystalline structure was produced by mechanical alloying of the elemental powders and the effect of subsequent heat treatment was investigated. The products were characterized using X-ray diffraction and microhardness measurements. The results showed that after 60 h of mechanical alloying, disordered B 2- NiTi phase can be obtained as a metastable phase at room temperature with grain size of 25 nm, lattice strain and high microhardness of 1.2% and 922 HV, respectively. After heat treatment, disordered structure transformed to ordered NiTi and a small amount of NiTi 2 and Ni 3 Ti phases. The long range order parameters of nanocrystalline NiTi were obtained to be 0.63 and 0.94 after annealing for 30 and 60 mins respectively. After 30 mins of heat treatment, 81.5% of Ni (or Ti ) atoms were on the right sites and after 60 mins it increased to 97%. Grain growth and decrease of microhardness and lattice strain were also observed after heat treatment. After 60 mins of heat treatment the grain size, lattice strain and microhardness of NiTi were 95, 0.09 and 624 HV respectively.

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Microstructural and Mechanical Properties Changes of Silicon Nitride Based Ceramic Using Post-Sintering Heat Treatment

Materials Science Forum ◽

10.4028/www.scientific.net/msf.727-728.1085 ◽

2012 ◽

Vol 727-728 ◽

pp. 1085-1091

Author(s):

José Vitor C. Souza ◽

O.M.M. Silva ◽

E.A. Raymundo ◽

João Paulo Barros Machado

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Fracture Toughness ◽

Grain Size ◽

Wear Resistance ◽

High Hardness ◽

Gas Pressure ◽

Low Density ◽

Nitrogen Gas ◽

Structural Applications

Si3N4based ceramics are widely researched because of their low density, high hardness, toughness and wear resistance. Post-sintering heat treatments can enhance their properties. Thus, the objective of the present paper was the development of a Si3N4based ceramic, suitable for structural applications, by sintering in nitrogen gas pressure, using AlN, Al2O3, and Y2O3as additives and post-sintering heat treatment. The green bodies were fabricated by uniaxial pressing at 80 MPa with subsequent isostatic pressing at 300 MPa. The samples were sintered at 1900°C for 1 h under N2gas pressure of 0.1 MPa. Post-sintering heat treatment was performed at 1500°C for 48 h under N2gas pressure of 1.0 MPa. From the results, it was observed that after post-sintering heat treatment there was a reduction of α-SiAlON phase and increase of β-Si3N4phase, with consequent changing in grain size, decrease of fracture toughness and increase of the Vickers hardness.

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