scholarly journals Crack Propagation in As-Extruded and Heat-Treated Mg-Dy-Nd-Zn-Zr Alloy Explained by the Effect of LPSO Structures and Their Micro- and Nanohardness

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3686
Author(s):  
Petra Maier ◽  
Benjamin Clausius ◽  
Asta Richter ◽  
Benjamin Bittner ◽  
Norbert Hort ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Crack Propagation ◽  
Treatment Time ◽  
Ringer Solution ◽  
Heat Treatment Condition ◽  
Compression Tests ◽  
Solid Solution Strengthening ◽  
Heat Treated ◽  
The Matrix ◽  
Zr Alloy

The investigation of the crack propagation in as-extruded and heat-treated Mg-Dy-Nd-Zn-Zr alloy with a focus on the interaction of long-period stacking-ordered (LPSO) structures is the aim of this study. Solution heat treatment on a hot extruded Mg-Dy-Nd-Zn-Zr (RESOLOY®) was done to change the initial fine-grained microstructure, consisting of grain boundary blocky LPSO and lamellar LPSO structures within the matrix, into coarser grains of less lamellar and blocky LPSO phases. C-ring compression tests in Ringer solution were used to cause a fracture. Crack initiation and propagation is influenced by twin boundaries and LPSO lamellae. The blocky LPSO phases also clearly hinder crack growth, by increasing the energy to pass either through the phase or along its interface. The microstructural features were characterized by micro- and nanohardness as well as the amount and location of LPSO phases in dependence on the heat treatment condition. By applying nanoindentation, blocky LPSO phases show a higher hardness than the grains with or without lamellar LPSO phases and their hardness decreases with heat treatment time. On the other hand, the matrix increases in hardness by solid solution strengthening. The microstructure consisting of a good balance of grain size, matrix and blocky LPSO phases and twins shows the highest fracture energy.

Effect of Heat Treatment on Al-40Si Alloy Modified by Sr Addition

2011 ◽  
Vol 378-379 ◽  
pp. 108-111
Author(s):  
Wei Ke An ◽  
An Hui Cai ◽  
Xiang Fu Tan ◽  
Xiao Song Li ◽  
Yun Luo
Keyword(s):  
Heat Treatment ◽  
Optical Microscope ◽  
Heat Treatment Condition ◽  
Solution Temperature ◽  
Primary Si ◽  
Optimal Heat Treatment ◽  
Heat Treated ◽  
Optimal Value ◽  
The Matrix ◽  
Temperature Solution

The Al-40Si alloy modified by 1.0 wt% Sr addition was heat-treated using L9(34) orthogonal test. The mechanical properties were measured. The microstructures were analyzed using optical microscope. After heat treatment, the hardness decreases about one times. The eutectic matrix and primary Si phase are both refined. The primary Si phase is refined and homogeneously distributes in the matrix with the solution temperature and time increasing. The optimal heat treatment condition is that the solution temperature, solution time, aging temperature, and aging time are 550 °C, 18 hours, 200 °C, and 5 hours, respectively. In addition, the theoretical optimal value for the hardness is 20.6 HRC, which is coherent with the practical optimal value.

Effect of Heat-Treatment Time on Microstructure and Mechanical Properties of Mg-5Gd-2Y-2Zn-0.5Zr Alloy

2012 ◽  
Vol 482-484 ◽  
pp. 1384-1389 ◽  
Author(s):  
Ling Gang Meng ◽  
Can Feng Fang ◽  
Peng Peng ◽  
Nai Pu Li ◽  
Qiong Zhu ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Grain Boundary ◽  
Treatment Time ◽  
Time Range ◽  
Lpso Phase ◽  
High Temperature Heat Treatment ◽  
Lpso Structure ◽  
The Matrix ◽  
New Type ◽  
The Stability

Microstructure evolution of Mg-5Gd-2Y-2Zn-0.5Zr alloy during high temperature heat-treatment at 500°C in the time range 10-70h was investigated. The results show that after adding the element Y, the as-cast Mg-5Gd-2Y-2Zn-0.5Zr alloy forms the Mg12Zn(Y,Gd) phase with 18R-LPSO structure at the grain boundary. During heat-treatment at 500°C, the stability of 18R-LPSO structure is weakened by Gd atoms, parts of LPSO phases dissolve gradually into the matrix with time prolonged and a new type Mg(Y,Gd)Zn phase come into being. LPSO phase in the grain boundary can ensure the ultimate tensile strength and elongation of the alloy, and effect of dissevering on the LPSO phase by Mg(Gd,Y)Zn phase results the decrease of UTS and elongation.

EFFECT OF HEAT TREATMENT ON MICROSTRUCTURE AND CORROSION RESISTANCE OF Ni-B-W-Mo COATING DEPOSITED BY ELECTROLESS METHOD

2018 ◽  
Vol 25 (08) ◽  
pp. 1950023 ◽  
Author(s):  
ARKADEB MUKHOPADHYAY ◽  
TAPAN KUMAR BARMAN ◽  
PRASANTA SAHOO
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Electrochemical Techniques ◽  
Sodium Molybdate ◽  
Medium Carbon Steel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Solid Solution Strengthening ◽  
Heat Treated ◽  
Electroless Coatings

The present work reports the deposition of a quaternary Ni-B-W-Mo coating on AISI 1040 medium carbon steel and its characterization. Quaternary deposits are obtained by suitably modifying existing electroless Ni-B bath. Composition of the as-deposited coating is analyzed by energy dispersive X-ray spectroscopy. The structural aspects of the as-deposited and coatings heat treated at 300[Formula: see text]C, 350[Formula: see text]C, 400[Formula: see text]C, 450[Formula: see text]C and 500[Formula: see text]C are determined using X-ray diffraction technique. Surface of the as-deposited and heat-treated coatings is examined using a scanning electron microscope. Very high W deposition could be observed when sodium molybdate is present in the borohydride-based bath along with sodium tungstate. The coatings in their as-deposited condition are amorphous while crystallization takes place on heat treatment. A nodulated surface morphology of the deposits is also observed. Vickers’ microhardness and crystallite size measurement reveal inclusion of W and Mo results in enhanced thermal stability of the coatings. Solid solution strengthening of the electroless coatings by W and Mo is also observed. The applicability of kinetic strength theory to the hardening of the coatings on heat treatment is also investigated. Corrosion resistance of Ni-B-W-Mo coatings and effect of heat treatment on the same are also determined by electrochemical techniques.

Experiment Investigation for Design on the Sensitization-Dependent Passivation Characteristics of AL-6XN in 3.5% NaCl Solution

2021 ◽  
Vol 21 (7) ◽  
pp. 3984-3988
Author(s):  
Kwang-Hu Jung ◽  
Seong-Jong Kim
Keyword(s):  
Heat Treatment ◽  
Potentiodynamic Polarization ◽  
Treatment Time ◽  
Test Methods ◽  
Double Loop ◽  
Nacl Solution ◽  
Heat Treated ◽  
Cyclic Potentiodynamic Polarization ◽  
Degree Of Sensitization ◽  
Characteristic Values

The sensitization and passivation characteristics of AL-6XN heat-treated for up to 24 h at 800 °C were evaluated through double loop electrochemical potentiodynamic reactivation (2 M H2SO4 + 0.01 M KSCN +2 M NaCl solution) and cyclic potentiodynamic polarization (3.5% NaCl solution) test methods. Furthermore, the dependence between the characteristic values (Epit, Erep, and degree of sensitization) was discussed. The σ phase was precipitated at the intergranular and intragranular in AL-6XN at 800 °C. When the heat treatment time exceeded 1 hour, AL-6XN occurred rapid sensitization due to the precipitation of σ phase. In a 3.5% NaCl solution, the passivation characteristics of AL-6XN with sensitivity were very poor and depended much on the degree of sensitization.

The Stability of γ ’-Co3(Al,W) Phase in Co-Al-W Ternary System

2010 ◽  
Vol 654-656 ◽  
pp. 448-451 ◽  
Author(s):  
Yuki Tsukamoto ◽  
Satoru Kobayashi ◽  
Takayuki Takasugi
Keyword(s):  
Heat Treatment ◽  
Ternary System ◽  
Microstructural Evolution ◽  
Treatment Time ◽  
Bulk Alloy ◽  
Epma Analysis ◽  
Heat Treated ◽  
Cold Rolled ◽  
The Stability ◽  
Couple Method

The thermodynamic stability ’- Co3(Al,W) phase (L12) in the Co-Al-W ternary system at 900 °C was investigated through microstructure and EPMA analysis on a heat-treated bulk alloy. To promote microstructural evolution, the bulk alloy was cold rolled before heat treatment. By heating at 900 °C, the ’ phase was formed discontinuously in contact with the -Co (A1) phase. With increasing heat treatment time, however, the fraction of ’ phase decreased while that of , CoAl (B2) and Co3W (D019) phases increased. These results are consistent with our previous work with a diffusion-couple method, indicating that the ’ phase is metastable, and the three phases of, CoAl and Co3W are thermodynamically stable at 900 °C.

Effect of Heat Treatment Condition on the Characteristics of MnO2 Added-Fe2TiO5 Ceramics for NTC Thermistors Using Local Iron Oxide

2018 ◽  
Vol 917 ◽  
pp. 64-68
Author(s):  
Wiendartun ◽  
Jaenudin Kamal ◽  
Dadi Rusdiana ◽  
Andhy Setiawan ◽  
Dani Gustaman Syarief
Keyword(s):  
Heat Treatment ◽  
Iron Oxide ◽  
Treatment Condition ◽  
Treatment Time ◽  
Heat Treatment Condition ◽  
Heat Treatment Time ◽  
Second Phase ◽  
Room Temperature Resistivity ◽  
Electrical Characteristics ◽  
Ntc Thermistor

A study on the effect of heat treatment condition on the characteristics of MnO2 added-Fe2TiO5 ceramics for NTC thermistor has been carried out. The ceramics were produced by pressing an homogenous mixture of Fe2O3 (local/ yarosite), TiO2 and MnO2 (2.0 mole %) powders in appropriate proportions to produce Fe2TiO5 based ceramics and sintering the pressed powder at 1050 °C for 3 hours in oxygen gas. Some sintered pellets were heat treated by heating them at 300 °C for 5, 15 and 25 minutes in Ar + 7% H2 gas. The XRD analyses showed that the Fe2TiO5 ceramics with and without heat treatment time had orthorhombic structure. No peak from second phase was observed from the XRD profiles. From the electrical characteristics data, it was known that the heat treatment could change the electrical characteristics of the Fe2TiO5 based-thermistor. The thermistor constant (B) and room temperature resistivity (ρRT) decreased with the increasing of heat treatment time. All ceramics made had thermistor characteristics namely B = 3459-7596 K and ρRT = 1.056-6936.062 MΩcm. Thermistor constant of the ceramics was relatively big, indicated that ceramics made from local iron oxide in this work fit the market requirement for NTC thermistor.

Effect of Heat Treatment on the Reactivity and Crystallinity of Coal-Char

2005 ◽  
Author(s):  
Shouyu Zhang ◽  
Junfu Lu ◽  
Jianmin Zhang ◽  
Qing Liu ◽  
Guangxi Yue
Keyword(s):  
Heat Treatment ◽  
Heat Treatment Temperature ◽  
Treatment Time ◽  
Treatment Temperature ◽  
Coal Char ◽  
Heat Treatment Time ◽  
Heat Treat ◽  
Heat Treated ◽  
Layer Stacking ◽  
Crystalline Growth

The effect of heat treatment on the reactivity and crystallinity of char prepared from the vitrinite of two coals (YX, JJ) was investigated by using XRD and TGA in this paper. The results from TGA show that the reactivity of the chars from YXV and JJV decreases with the increase of heat treatment temperature. The reactivity of YXV char decreases quickly and significantly as heat treatment time increases. However, after heat treatment time of 60 min, it decreases slowly. The effect of heat treatment time on the reactivity of JJV char is small. The results from XRD show that the crystallinity of coal-char is determined by the intensity of heat treatment. When heat treatment time is more than 60 minutes, the turbostratic crystallite of YXV char prepared under 900°C changes remarkably and becomes more orderly. The aromatic layer stacking heights (Lc) of YXV Char when heat treated above 900°C increased with the increase of heat treatment time. The effect of heat treat time on Lc of JJV char is small, but under heat treatment temperature of 1200°C, the crystalline of JJV char grows distinctly. There is a good parallel relationship between the crystalline growth and deactivation of the chars. It can be concluded that the growth of the crystalline is the main reason for the deactivation of coal-char.

The Effect of Incomplete Solution Treatment on the Tensile Behavior and Mechanical Anisotropy of 2195 Aluminum Lithium Alloy

2019 ◽  
Vol 22 ◽  
pp. 109-117
Author(s):  
Wesley Walker ◽  
Rudolf Marloth ◽  
Ye Thura Hein ◽  
Omar S. Es-Said
Keyword(s):  
Heat Treatment ◽  
Treatment Time ◽  
Cold Work ◽  
Rolling Direction ◽  
Solution Treatment ◽  
Tensile Behavior ◽  
Mechanical Anisotropy ◽  
Aluminum Lithium Alloy ◽  
Heat Treated ◽  
Aluminum Lithium

This study aimed to characterize the effects of incomplete solution treatment time on the tensile behavior of 2195 Al-Li alloy. Two sets of plates of 2195 Al-Li alloy received solution heat treatment. One set received the prescribed treatment, held in the furnace for 30 minutes after the material had reached 507°C. The other set was in the furnace for only 30 minutes and did not reach 507°C until after about 15 to 20 minutes. Both set of plates were water quenched. Samples from the plates were then stretched 2.5-3% or 6%, rolled 6%, and rolled 24%, at 0°, 45°, and 90° relative to the rolling direction of the as-received material. The samples were aged at 143°C for 36 hours and air-cooled. Tensile specimens were milled out at 0°, 45°, and 90° relative to the original rolling direction. Tensile testing was performed on all samples. The incomplete heat treatment (incomplete solution treatment) resulted in a significant reduction in strength. This was probably due to the formation of fewer T1 precipitates after aging, thereby reducing the amount which could nucleate during cold work. The fully heat treated samples had higher percent yield strength, ultimate strength, and elongation.

Effect of heat treatment time on cycle performance of LiMn2O4 with “Nano Inclusion” for lithium ion batteries

RSC Advances ◽  
2015 ◽  
Vol 5 (53) ◽  
pp. 42455-42460 ◽  
Author(s):  
Shogo Esaki ◽  
Motoaki Nishijima ◽  
Shigeomi Takai ◽  
Takeshi Yao
Keyword(s):  
Heat Treatment ◽  
Lithium Ion Batteries ◽  
Discharge Capacity ◽  
Treatment Time ◽  
Lithium Ion ◽  
Heat Treatment Time ◽  
Cycle Performance ◽  
Heat Treated

The cycle performance of LiMn2O4 with “Nano Inclusions” is higher than that of LiMn2O4 without “Nano Inclusions” and the discharge capacity of LiMn2O4 with “Nano Inclusions” heat-treated for 4 h surpassed that of LiMn2O4 without it at over 31 cycles.

Effect of Heat Treatment on Decay Resistance of Chinese Fir and Pine

2012 ◽  
Vol 468-471 ◽  
pp. 1118-1122
Author(s):  
Yan Jun Li ◽  
Lan Xing Du ◽  
Gou Ying Hu ◽  
Xing Xia Ma
Keyword(s):  
Heat Treatment ◽  
Moisture Content ◽  
Treatment Time ◽  
Brown Rot ◽  
Decay Resistance ◽  
Chinese Fir ◽  
Heat Treatment Time ◽  
White Rot ◽  
Heat Treated ◽  
Brown Rot Fungus

To enhance decay resistance, the effect of heat treatment and the variation of chemical composition on Chinese Fir and Pine were investigated in this study — heat treatment temperature was 170°C, 190°C and 210°C, respectively, heat treatment time was 2, 3 and 4hours, respectively. Both of them were subsequently exposed to white-rot fungus and brown-rot fungus. The results showed that:(1) With the increasing of the heat treatment, decay resistance of Chinese Fir and Pine were improved, anti-corrosion of Pine after being heat treated at 190°C which were exposed to write-rot fungus can reach I, anti-corrosion of Chinese Fir after being heat treated at 170°C treated which were exposed to brown-rot fungus could reach I yet, After being heat treated at 210°C for 3 hours , the Chinese fir samples had no measurable weight loss when exposed to the write-rot fungus.(2) There was no remarkable influence on both Chinese Fir and Pine by heat treatment time.(3) The moisture content of Chinese Fir and Pine were lower than the moisture content that the rot fungus need, macromolecule chains such as cellulose and hemicellulose broke down, their contents decreased, and the hemicellulose decomposed into acetic acid, they prevented the growth of rot fungus.

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