scholarly journals Evaluation of the Aging Effect on the Microstructure of Co-28Cr-6Mo-0.3C Alloy: Experimental Characterization and Computational Thermodynamics

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 581 ◽  
Author(s):  
Shahab Zangeneh ◽  
Ersoy Erisir ◽  
Mahmoud Abbasi ◽  
Ali Ramazani
Keyword(s):  
Martensitic Transformation ◽  
Solution Treatment ◽  
Aging Effect ◽  
Sample Solution ◽  
Solution Temperature ◽  
Solution Treated ◽  
The Matrix ◽  
Fcc Phase ◽  
Experimental Findings ◽  
Lamellar Type

In the current research, we studied the role of the solution treatment and aging on the microstructure of a Co–28Cr–5Mo–0.3C alloy. We used metallographic observations, scanning electron microscopy (SEM), and hardness measurements for the evaluations. We also made a comparison between the phase equilibrium calculated with Thermo-Calc, using TCFE8 and TCNI8 thermodynamic databases and experimental findings. The experimental results showed that the transformation of the metastable FCC phase to the HCP phase during aging was extremely sensitive to the solution treatment prior to aging. The effect of the increase in the solution temperature and time was detectable through promotion of the martensitic transformation during quenching in which HCP1 (straight bands) and HCP2 (lamellar-type constitution) phases had developed. In contrast, a low solution temperature and time caused most of the primary carbides to remain in an undissolved condition in the matrix; therefore, during aging, no sign of the FCC to HCP1 (straight bands) phase transformation could be observed. However, we observed the formation of the HCP2 phase (lamellar-type constitution) at the grain boundaries. In addition, the X-ray diffraction pattern indicated that the sample solution treated at lower temperatures and shorter times had a stronger martensitic transformation during aging compared to the sample solution treated at higher temperatures and longer times. Hardness measurements confirmed the results. Thermodynamical calculations showed that an agreement existed between the experiments and calculations. We also discuss the results from the TCFE8 and TCNI8 databases.

Effect of Solution Treatment on Second Phase Dissolution for an Al-9.2Zn-2.0Mg-1.9Cu Alloy

2020 ◽  
Vol 993 ◽  
pp. 321-326
Author(s):  
Hong Wei Liu ◽  
Kai Wen ◽  
Xi Wu Li ◽  
Zhi Hui Li ◽  
Li Zhen Yan ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Solution Treatment ◽  
Optical Microscope ◽  
Solution Temperature ◽  
Second Phase ◽  
Dsc Analysis ◽  
Scanning Calorimetry ◽  
Phase Dissolution ◽  
Solution Treated ◽  
The Matrix

The second phase dissolution of Al-9.2Zn-2.0Mg-1.9Cu alloy conducted by various temperatures of 2h was researched with the help of optical microscope (OM), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), electrical conductivity and differential scanning calorimetry (DSC) analysis. The results gave rise to the second phase existence of Mg(Zn,Cu,Al)2 and Fe-containing phases in the as-extruded alloy. When the alloy solution treated with a temperature varied from 450°C to 470°C, a small quantity of Mg(Zn,Cu,Al)2 phase still existed in the alloy while its content exhibited a decrement trend with the solution temperature rose. For the alloy solution treated at a temperature of 475°C, Mg(Zn,Cu,Al)2 phase dissolved into the matrix completely while Fe-containing phase still remained. The electrical conductivity of quenched alloy decrease with the solution temperature increase and reached a minimum value at 470°C, and then rose slightly for the solution temperature of 475°C.

Main Alloying Influence on Second Phase Dissolution during Solution Treatment of Al-Zn-Mg-Cu Alloys

2021 ◽  
Vol 1035 ◽  
pp. 3-9
Author(s):  
Hong Wei Liu ◽  
Kai Wen ◽  
Wei Cai Ren ◽  
Xi Wu Li ◽  
Yong An Zhang ◽  
...  
Keyword(s):  
Solution Treatment ◽  
Solution Temperature ◽  
Second Phase ◽  
Dsc Analysis ◽  
Phase Dissolution ◽  
Cu Alloys ◽  
Residual Phase ◽  
Solution Treated ◽  
The Matrix ◽  
Second Phases

Second phase dissolution of Al-Zn-Mg-Cu alloys during solution treatment was closely associated with the content of main alloying elements. In present work, the phase characteristics of several Al-Zn-Mg-Cu alloys with various main alloying contents were investigated, and the second phase dissolution of these alloys during solution treatment was analyzed. The results showed that the extrusion alloys possessed abundant second phases, mainly including Mg(Zn,Cu,Al)2 phase and Fe-rich particles. The DSC analysis proved that the larger endothermic peak corresponded to the alloy with larger main alloying content, and the XRD spectrogram also backed up the advantage of Mg(Zn,Cu,Al)2 phase. After solution treated at 450°C, the residual phases remained in the alloys and the quantity of them were positively correlated with the main alloying content. With the increase of solution temperature, the electrical conductivity of the alloys showed a decremental trend, while the alloys with relatively low main alloying contents exhibited an inversion at the solution temperature of 475°C. The SEM observation demonstrated that no Mg(Zn,Cu,Al)2 phase was observed in the alloys with relatively low main alloying contents while seldom still remained in the alloy with high main alloying content after solution treated at 470°C. After solution treated at 475°C, Mg(Zn,Cu,Al)2 phase completely dissolved into the matrix for the alloy with high main alloying content. The statistics of residual phase quantity also proved this.

Effect of Solution Treatment on Microstructures and Hardness of Mg-Gd-Y-Zr Alloy

2014 ◽  
Vol 937 ◽  
pp. 182-186
Author(s):  
Quan An Li ◽  
Lei Lei Chen ◽  
Wen Chuang Liu ◽  
Xing Yuan Zhang ◽  
Hui Zhen Jiang
Keyword(s):  
Vickers Hardness ◽  
Cast Alloy ◽  
Solution Treatment ◽  
Hardness Measurement ◽  
Solution Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Solution Treated ◽  
Primary Particles ◽  
Zr Alloy

The influence of the solution treatment (at the temperature of 500-520°C for 4-12 h) on microstructures and mechanical properties of Mg-Gd-Y-Zr alloy was investigated by means of optical microscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) and Vickers hardness measurement. The as-cast alloy contains a microstructure consisting of α-Mg matrix, Mg5Gd phase and Mg24Y5phase. With increasing solution temperature and time, the quantity of the primary particles (Mg5Gd and Mg24Y5) in the alloy continually decreased, and the degree of recrystallization gradually increased, which result in the gradual decrease of the Vickers hardness of the solution-treated alloys.

Effect of the Two-Step Solution Heat Treatment on the Microstructure of Semisolid Cast 7075 Aluminum Alloy

2012 ◽  
Vol 488-489 ◽  
pp. 243-247 ◽  
Author(s):  
Saowalak Kongiang ◽  
Thawatchai Plookphol ◽  
Jessada Wannasin ◽  
Sirikul Wisutmethangoon
Keyword(s):  
Heat Treatment ◽  
Treatment Condition ◽  
Solution Heat Treatment ◽  
Solution Treatment ◽  
Heat Treatment Condition ◽  
Single Step ◽  
Eutectic Phase ◽  
Solution Treated ◽  
The Matrix ◽  
Black Particle

Effect of the two-step solution heat treatment on the microstructure of semisolid cast 7075 aluminium alloy has been studied. The microstructure of the as-cast specimens mainly consisted of matrix-α (Al) and grain boundary (GB)-eutectic phase (α-Al + Mg(Zn,Cu,Al)2). After solution treating, coarse black particles were found to form in the single-step solution treated specimens at the condition of 450 °C for 8 h and 480 °C for 1 h, respectively. Two-step solution heat treatment resulted in the reduction of coarse black particle formation while maintaining the same amount of eutectic MgZn2phase dissolution as the high temperature single-step solution treatment. Therefore, the two-step solution heat treatment enables alloying elements dissolved into the matrix without overheating and hence decreases coarse black particles. The optimum two-step solution heat treatment condition derived from this study was 400 °C for 8 h + 450 °C for 4 h.

Microstructure and Tensile Properties of Mg-4Zn-2Sn-2Al Alloy

2013 ◽  
Vol 747-748 ◽  
pp. 398-403 ◽  
Author(s):  
Dong Qing Zhao ◽  
Xu Guang Dong ◽  
Xin En Zhang ◽  
An Jiang Gao ◽  
Ji Xue Zhou ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Tensile Properties ◽  
Aging Process ◽  
Supersaturated Solid Solution ◽  
Cast Alloy ◽  
Solution Treatment ◽  
Solution Treated ◽  
The Matrix ◽  
Alloy Increase

The microstructures and tensile properties of as-cast, solution-treated and aged Mg-4Zn-2Sn-2Al (wt.%) alloy have been investigated. The microstructure of the as-cast alloy consists of α-Mg, Mg2Sn and Mg32(Al,Zn)49 phases. The yield tensile strength and the ultimate tensile strength of the as-cast alloy are 87.7 MPa and 241.3 MPa, respectively, and the elongation reaches to 18.8% showing excellent ductility. After solution treatment, all of the Mg32(Al,Zn)49 phase and the majority of Mg2Sn particles have dissolved into the matrix. During aging process, Mg2Sn phase precipitates from the α-Mg supersaturated solid solution. With the precipitation strengthening of Mg2Sn phase, the yield tensile strength and the ultimate tensile strength of the alloy increase to 112.5 MPa and 280.4 MPa, respectively, while, the elongation decreases to 12%.

Effect of Solution Treatment on Corrosion Resistance of the Biodegradable NZ20K Alloy

2016 ◽  
Vol 849 ◽  
pp. 196-202
Author(s):  
Yang Fei ◽  
Xiao Bo Zhang ◽  
Zhi Xin Ba ◽  
Zhang Zhong Wang
Keyword(s):  
Corrosion Resistance ◽  
Electron Microscope ◽  
Corrosion Rate ◽  
Scanning Electron Microscope ◽  
Biomedical Applications ◽  
Solution Treatment ◽  
Solution Temperature ◽  
Solution Treated ◽  
Different Temperatures ◽  
Scanning Electron

In order to study the effect of solution temperature on corrosion resistance of Mg alloy for biomedical applications, microstructure and corrosion behavior of Mg-2.25Nd-0.11Zn-0.43Zr (NZ20K) alloy solution treated at different temperatures were investigated by using a scanning electron microscope (SEM) equipped with an electron dispersive spectroscope (EDS), electrochemical and mass loss tests. The results show that the grains grow and precipitations decreases with increasing the solution temperature. The corrosion rate decreases firstly and then increases with increasing solution temperature, and the best corrosion resistance of the NZ20K alloy is obtained at the temperature of 540 °C.

Microstructure and Tensile Properties of a Mg-5Sn-4Al Alloy

2011 ◽  
Vol 287-290 ◽  
pp. 343-347 ◽  
Author(s):  
Shou Qiu Tang ◽  
Ji Xue Zhou ◽  
Yuan Sheng Yang ◽  
Chang Wen Tian
Keyword(s):  
Tensile Strength ◽  
Tensile Properties ◽  
Aging Process ◽  
Room Temperature ◽  
Fine Particles ◽  
Solution Treatment ◽  
Cast Sample ◽  
Solution Treated ◽  
The Matrix ◽  
Alloy Increase

The microstructure and tensile properties at room temperature of as-cast, solution-treated and aged samples of a Mg-5Sn-4Al (wt%) alloy are investigated. The microstructure of the as-cast sample consists of a-Mg primary, Mg2Sn and Mg17Al12divorced eutectic, secondary precipitations Mg17Al12and Mg2Sn. After solution treatment, all the Mg17Al12particles and the majority of Mg2Sn phases are dissolved into the matrix and the tensile strength and the elongation of the alloy increase obviously. During aging process many fine particles of Mg2Sn precipitate which result in the improvement of the yield strength.

Effect of Stepped Solution Treatment on Microstructure and Properties of AA7085 Aluminum Alloy

2011 ◽  
Vol 239-242 ◽  
pp. 786-792
Author(s):  
Chun Mei Li ◽  
Zhi Qian Chen ◽  
Su Min Zeng ◽  
Nan Pu Cheng ◽  
Zhen Hua Geng ◽  
...  
Keyword(s):  
Melting Temperature ◽  
Solution Treatment ◽  
Solution Temperature ◽  
Tensile Fracture ◽  
Tensile Fracture Surface ◽  
The Matrix ◽  
Initial Melting ◽  
Statistic Theory ◽  
Lower Temperature ◽  
Multi Phase

The effect of stepped solution treatment on the mechanical properties and the microstructure of AA7085 have been investigated compared to AA7050. Optical and electron microscopy observation and electron probe microanalysis were used to analyze the microstructure and tensile fracture surface of AA7085 and AA7050 processed via various treatment schedules. Besides, X-ray diffractometer and differential scanning calorimeter were used to seek the differences of microstructure characters between AA7085 and AA7050. The results indicate that higher content of Zn along with lower content of Mg and Cu and strictly confined Fe and Si made the matrix of AA7085 get a larger single phase and a higher melting temperature of multi-phase eutectics. By using a lower temperature pretreatment, the initial melting temperature of the alloys can be increased. Consequently complete dissolution of remnant constituents was achieved without overheating. Based on thermodynamics statistic theory, the supersaturation degree of the matrix and the density of cavity may be increased with the elevation of the lattermost solution temperature, which resultes in the increase of fracture toughness and optimization of the microstructure after aging.

Effect of Solution Treatment Temperature on Properties of an Al11Si3Cu0.35Mg Cast Alloy

2007 ◽  
Vol 353-358 ◽  
pp. 357-360
Author(s):  
Gui Qing Wang ◽  
Zhong Kui Zhao ◽  
Yan Liu
Keyword(s):  
Mechanical Properties ◽  
Cast Alloy ◽  
Solution Treatment ◽  
Treatment Temperature ◽  
Solution Temperature ◽  
Solution Treatment Temperature ◽  
Permanent Mold ◽  
Incipient Melting ◽  
Solution Treated ◽  
Alloy Properties

The present work was performed on Al11Si3Cu0.35Mg samples cast in a permanent mold preheated to 200 °C. The tensile properties for varies solution treated samples aged at 200 °C for 6 h were examined in order to study the influence of solution temperature on the alloy properties. The dissolution of copper-containing phases and the incipient melting were analyzed for cast samples solution treated in the temperature range 500~520 °C for 8 h followed by quenching in water. The influence of the incipient melting on mechanical properties has been discussed.

Microstructure Evolution and Mechanical Properties of Mg-3Zn-0.5Er-0.5Al Alloy

2015 ◽  
Vol 816 ◽  
pp. 446-450
Author(s):  
Xiao Bing Zheng ◽  
Wen Bo Du ◽  
Ke Liu ◽  
Zhao Hui Wang ◽  
Shu Bo Li
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Tensile Strength ◽  
Microstructure Evolution ◽  
Mass Fraction ◽  
Solution Treatment ◽  
Solid Solution Treatment ◽  
Solution Treated ◽  
Quaternary Phase ◽  
The Matrix

The microstructure evolution of the Mg-3Zn-0.5Er-0.5Al (mass fraction, %) alloy under the different condition was investigated. The results showed that as-cast Mg-3Zn-0.5Er-0.5Al alloy mainly consisted of primary large irregular Mg4Zn7 phase and needlelike (Mg, Zn, Er, Al) quaternary phase. Mg4Zn7 phase almost dissolved into the matrix after solid solution treatment at 400 oC for 10 h, while the (Mg, Zn, Er, Al) quaternary phase still existed. The solution treated alloy was extruded at 250 °C. The ultimate tensile strength of the as-extruded alloy was approximately 268 MPa and the YTS was approximately 163 MPa companying with an elongation of 28%. The tensile strength of the as-extruded alloy improved obviously, which was mainly attributed to the grain refinement.

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