scholarly journals Effect of the δ Phase on the Tensile Properties of a Nickel-Based Superalloy

Metals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1153 ◽  
Author(s):  
Qiang Zhu ◽  
Gang Chen ◽  
Chuanjie Wang ◽  
Lukuan Cheng ◽  
Heyong Qin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Boundary ◽  
Aging Time ◽  
Aging Treatment ◽  
Single Mode ◽  
Tensile Tests ◽  
Fracture Site ◽  
Precipitation Method ◽  
Inhomogeneous Strain ◽  
Δ Phase

Nickel-based superalloys are widely used in aerospace and other fields due to their excellent properties. In this study, the aging treatment and tensile tests of a GH4169 alloy were carried out. The effects of the δ phase on the alloy’s mechanical properties and fracture behavior were studied. The results showed that the appearance of the δ phase changed from a short rod shape to a needle shape with an increase in aging time. The precipitation method changed from a single mode of precipitation along the grain boundary to two modes of precipitation along the grain boundary and direct precipitation inside the grain. The yield strength and ultimate tensile strength of the alloy first increased and then decreased with an increase in aging time and were related with the microstructure of the δ phase. The similar Widmanstatten structure was not conducive to the mechanical properties of the alloy. The distribution of the δ phase led to the generation of inhomogeneous strain and limited the surface roughening during plastic deformation. The voids initiated at the interface between the δ phase and the matrix γ phase or directly from the δ phase fracture site.

Effect of Artificial Aging on Microstructures and Mechanical Properties of Extruded Mg Alloy ZK60

2014 ◽  
Vol 697 ◽  
pp. 72-75
Author(s):  
De Liang Yin ◽  
Jian Qiao ◽  
Hong Liang Cui
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Aging Time ◽  
Artificial Aging ◽  
Aging Treatment ◽  
Tensile Tests ◽  
Tensile Yield Strength ◽  
Uniaxial Tensile ◽  
Fracture Elongation ◽  
Strength And Ductility

An extruded ZK60 magnesium alloy was subjected to artificial aging at 180 oC for an investigation of the effect of aging time on its precipitation behavior and mechanical properties. Uniaxial tensile tests were conducted to obtain the mechanical properties. Optical microscopy and transmission electron microscopy (TEM) were employed to observe microstructure change before and after aging treatment. It is shown that, both tensile yield strength and ultimate tensile strength increases with aging time. The fracture elongation after aging for 20 h reaches up to 21.0%, and the yield strength increases to 269.5 MPa, 19.4% higher than that of extruded specimens (un-aged), showing a good match of strength and ductility. Three newly-formed precipitates were observed after aging for over 20 h, among which particulate and dispersive precipitates should be responsible for the good combination of strength and ductility.

Effects of the Aging Time and Temperature on the Microstructures and Mechanical Properties of 6082 Aluminum Alloy Extrusions

2013 ◽  
Vol 652-654 ◽  
pp. 1035-1042
Author(s):  
Tao Wu ◽  
Xian Fei Ding ◽  
Jing Sun ◽  
Wei Dong Zhang ◽  
Dong Bai Sun ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Aging Time ◽  
Tensile Elongation ◽  
Aging Treatment ◽  
Longitudinal Direction ◽  
Tensile Tests ◽  
Main Task ◽  
6082 Aluminum Alloy ◽  
Effects Of Aging

The main task of this work was to study the effects of aging time and aging temperature on the microstructure and mechanical properties of 6082 aluminum alloy extrusions. Artificial aging was performed on the alloy extrusions at the temperatures of 150, 175 and 200 °C for the aging times of 4, 8 and 12 h. The microstructure evolution of the aluminum alloy extrusions with increase of the aging time and temperature was investigated by Field Emission Scanning Electron Microscope (FESEM). For the purpose of how the aging process affected the mechanical properties, tensile tests were performed. The results showed that the optimum aging treatment was 175 °C/4 h. Under this condition, the tensile strength (Rm) and the yield strength (Rp) in the longitudinal direction of the extrusions reached the maximum value more than 350MPa and 320MPa, respectively, and the tensile elongation (A) was more than 15%.

Effect of Aging Treatment on Properties and Microstructure of an Al-7.5Zn-1.3Mg-1.4Cu-0.12Zr Alloy

2010 ◽  
Vol 638-642 ◽  
pp. 273-278 ◽  
Author(s):  
Xi Wu Li ◽  
Bai Qing Xiong ◽  
Yon Gan Zhang ◽  
Guo Jun Wang ◽  
Zhi Hui Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Electrical Conductivity ◽  
Grain Boundary ◽  
Response Rate ◽  
Aging Treatment ◽  
Aging Response ◽  
Peak Aging

In this study, the effect of various aging treatment (T6 and T7 treatment) on the mechanical properties, electrical conductivity and the microstructure of an Al-7.5Zn-1.3Mg-1.4Cu-0.12Zr alloy has been investigated. The results show that with elevating the aging treatment temperatures, the aging response rate is greatly accelerated. When T6 temper is performed at 140°C for 12h, as compared to peak aging for 24h at 120°C, the UTS and the corresponding Elongation values keep the same level, whereas the TYS and the electrical conductivity obviously increase by 5% and 9%, which is up to 560 MPa and 22.6 MS/m, respectively. And there are clear PFZs along the grain boundary and slightly coarser precipitates inside the grain. GPI zones, GPII zones and η' phases are major precipitates for the alloy under T6 condition. When T7 temper is performed on the alloy, the main precipitates are GPII zones, η′ and η phases. The coarser precipitates inside the grain and discontinuous grain boundary precipitates are favorable to electrical conductivity, which decrease the strength of 5~17% compared to T6 treatment. After T76 treatment (i.e., 110°C/6 h + 160°C/6 h), the UTS, TYS, Elongation and electrical conductivity values were 540 MPa, 510 MPa, 16.7% and 23.5 MS/m, respectively.

Functional Gradation in Precipitation Hardenable AA7075 Alloy by Differential Cooling Strategies

2021 ◽  
Vol 883 ◽  
pp. 159-166
Author(s):  
Emad Scharifi ◽  
Moritz Roscher ◽  
Steffen Lotz ◽  
Ursula Weidig ◽  
Eric Jägle ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Phase Particle ◽  
Hot Stamping ◽  
Aging Treatment ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Material Strength ◽  
Second Phase ◽  
Contrast Imaging ◽  
Forming Tools

Inspired by steel forming strategies, this study focuses on the effect of differential cooling on mechanical properties and precipitation kinetics during hot stamping of high strength AA7075 alloy. For this aim, different forming strategies were performed using segmented and differentially heated forming tools to provide locally tailored microstructures. Upon processing, uniaxial tensile tests and hardness measurements were used to characterize the mechanical properties after the aging treatment. Microstructure investigations were conducted to examine the strengthening mechanisms using the electron channeling contrast imaging (ECCI) technique in a scanning electron microscope (SEM). Based on the obtained results, it can be deduced that the tool temperatures play a key role in influencing the mechanical properties. Lower tool temperatures result in higher material strength and higher tool temperatures in lower mechanical properties. By changing the cooling rate with the use of differently heated forming tools, the mechanical properties can be controlled. Microstructure investigations revealed the formation of very fine and homogeneously distributed particles at cooled zones, which were associated with elevated mechanical properties due to the suppression of second phase particle formation during cooling. In contrast, coarse particles were observed at lower cooling rates, explaining the lower material strength found in these zones.

Processing of high strength Mg–9Gd–3Nd–1Sn–1Zn–0.6Zr alloy by hot rolling and subsequent aging

2020 ◽  
Vol 10 (7) ◽  
pp. 1020-1031
Author(s):  
Zehua Yan ◽  
Yandong Yu ◽  
Yanchao Sang ◽  
Yiming Yao ◽  
Jiahao Qian
Keyword(s):  
Grain Boundary ◽  
Aging Time ◽  
Hot Rolling ◽  
Aging Treatment ◽  
High Strength ◽  
Subsequent Aging ◽  
Free Zone ◽  
Treatment Conditions ◽  
Peak Aging ◽  
Equilibrium Phases

Magnesium alloy plates can be strengthened by rolling, however, it is easy to crack or even break when the reduction of Mg–RE alloys is too large. Herein, the strengthening mechanical of the Mg–9Gd–3Nd–1Sn–1Zn– 0.6Zr alloy under different treatment conditions were investigated after hot-rolling to 80% reduction in thickness (0.8 mm) by multi-step methods. Furthermore, the rolled alloy by aging strengthening are explored. The results show that the hot-rolled alloy with 80% reduction are basically composed of dynamically recrystallized grains with the size of about 60 m, improving the mechanical properties significantly. The precipitates within grains undergo SSSS→ β″ → β′ phase transformation with the aging treatment up to 200 °C. Fine β″ precipitates were found in the grains of the rolled alloy under aged time (2 h), while β″ precipitates changed into β′ phase when the aging time was extended to 32 h. The base phase which is perpendicular to phase was precipitated in the alloy in longer aging time (96 h). In addition, the thickness of precipitates and precipitation-free zone (PFZ) at the grain boundary gradually increased as the time went on. Meanwhile, the discontinuous equilibrium phases at the grain boundary are gradually become continuous. The ultimate tensile strength and hardness were reached to 431.14 MPa, 105.9 HV at peak-aging, in addition, the elongation is reached to 3.11%, respectively. The formation of crack sources is due to the stress concentration between the brittle PFZ and the magnesium matrix, which leads to the decrease of ductility.

Microstructure and Mechanical Properties of Aged Mg-12Gd-2Y-0.5Zr Alloy Addition with Sb

2011 ◽  
Vol 261-263 ◽  
pp. 693-696
Author(s):  
Ke Jie Li ◽  
Quan An Li
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Aging Treatment ◽  
Tensile Tests ◽  
Precipitation Strengthening ◽  
Aged Alloy ◽  
Long Period ◽  
Casting Technology ◽  
Alloy Addition ◽  
Solution Strengthening

The Mg-12Gd-2Y-0.5Sm-0.5Sb-0.5Zr (wt.%) alloy was prepared by casting technology. The microstructure was investigated after solution and aging treatment (i.e. T6 heat treatment). Tensile tests were performed at a crosshead speed of 1 mm/min at ambient and elevated temperature atmosphere. The results show that the aged alloy was mainly composed of α-Mg matrix, Mg5Gd phase and dispersed long-period ordered β' precipitates. At 523K, the alloy has shown the superior tensile strength (i.e. 345.5 MPa). The strength mechanism was solution strengthening of RE and precipitation strengthening of dispersive LPO structure β' and stable Mg5Gd precipitatesin Mg matrix.

Enhancement of Mechanical Properties of Cast Beta-Type Titanium Alloy by Aging Treatment

2018 ◽  
Vol 929 ◽  
pp. 42-49
Author(s):  
Zuldesmi Mansjur ◽  
Hendro Maxwel Sumual
Keyword(s):  
Mechanical Properties ◽  
Aging Time ◽  
Vickers Hardness ◽  
Aging Temperature ◽  
Dendritic Structure ◽  
Solution Treatment ◽  
Aging Treatment ◽  
High Oxygen Content ◽  
Precision Casting ◽  
Β Phase

Beta type Ti-29Nb-13Ta-4.6Zr alloy (TNTZ) is one of the titanium alloys which have gained much attention in dental applications. Dental precision casting is predominant for fabricating dental prostheses. However, there is a possibility for the mechanical properties of its casting to be degraded because of a α case, shrinkages and pores and a dendrite structure. One of the ways to enhance their mechanical properties is heat treatment process. Therefore, the aim of this study is to investigate the effect of aging treatment on mechanical properties and microstructure of TNTZ cast into magnesia based mold in order to improve its mechanical properties. As results, the Vickers hardness of the cast TNTZ after solution treatment is larger than that of the wrought TNTZ. The aging curve of the cast and the wrought TNTZ at an aging temperature of 673 K and 723 K exhibit almost similar pattern. For each aging time, the higher the aging temperature, the smaller the Vickers hardness for both alloys. Microstructures of cast TNTZ at various aging conditions consist of a dendritic structure and the average diameters of their grain size are around 40 μm. The diffraction peaks of precipitation of α and β phase s are detected in under aging (UA), peak aging (PA) and over aging (OA) conditions for both aging temperatures. However, the diffraction peak of ω phase is observed only in OA condition for cast TNTZ at aging temperature of 673 K. The highest tensile strength of the cast TNTZ and the wrought TNTZ at both aging temperatures are in PA condition and the elongation decrease continuously by increasing aging time. The tensile strengths of cast TNTZ in UA, PA and OA conditions at an aging temperature of 723 K are lower and their elongations are higher in comparison with those of 673 K. The high oxygen content seems to contribute to the poor elongation. SEM fractographs of the cast TNTZ at aging temperatures of 673 and 723 K in UA, PA and OA conditions show the brittle morphology with intergranular fracture that increases with increasing of aging time.

The Effects of Two-Stage Aging on the Microstructure and Mechanical Properties of the New Al-Si-Cu-Mg Alloy

2016 ◽  
Vol 850 ◽  
pp. 581-586 ◽  
Author(s):  
Yan Zheng ◽  
Cong Xu ◽  
Wen Long Xiao ◽  
Hiroshi Yamagata ◽  
Guo Fu Ji ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Aging Time ◽  
Aging Treatment ◽  
Experimental Results ◽  
Mg Alloy ◽  
Casting Alloy ◽  
Two Stage ◽  
Microstructure And Mechanical Properties

Two-stage aging treatments were applied to Al-6Si-2Cu-0.5Mg casting alloy, and the influence of aging treatment parameters on the microstructure and mechanical properties was investigated. The experimental results indicated that the microstructure and mechanical properties of Al-6Si-2Cu-0.5Mg alloy were significantly influenced by the aging time and temperature, and the elongation remarkably increased with the aging time increasing before 7 h. In the case of the alloy aged at 200°Cfor 2h, higher hardness and tensile strength were obtained, which may be attributed to precipitation of a large amount of Cu-rich phases. However, the higher elongation was achieved in the alloy under 200°C aging treatment for 5h, while its hardness and tensile strength slightly decreased. It is mainly due to the amount of the Cu-rich phases decrease slightly, but the morphology of the phases evolved from plate-like to bulk-like structure.

The Effect of Aging Heat Treatment on the Mechanical Properties of Cu-Al-Fe-(x) Alloys

2011 ◽  
Vol 467-469 ◽  
pp. 257-262
Author(s):  
Guo Fa Mi ◽  
Jin Zhi Zhang ◽  
Hai Yan Wang
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Aging Time ◽  
Solution Treatment ◽  
Aging Treatment ◽  
Experimental Result ◽  
Electric Resistance ◽  
Suitable Heat Treatment ◽  
Ni Alloy

Alloys were produced by casting of Cu-Al-Fe-Be and Cu-Al-Fe-Ni aluminum bronzes and aged. The microstructures and mechanical properties were evaluated. The results indicated that solution and aging treatment can significantly improve the plasticity of Cu-Al-Fe-Be and Cu-Al-Fe-Ni, while the strength and hardness remained in the quenched level. Extending the aging time can effectively enhance the mechanical properties of alloys, and the longer the aging time, the higher the electric resistance of alloys. According to the results, the mechanical properties of the Cu-Al-Fe-Be alloy can be improved remarkably by solution treatment for 120 min at 950°C, followed by aging treatment for 120 min at 350°C, and quenched. While the most suitable heat treatment for the Cu-Al-Fe-Ni alloy was solution treatment 120 min at 950°C, followed by aging for 120 min at 450°C, and quenched. The experimental result also suggested that the Cu-Al-Fe-Be alloy possessed higher hardness and tensile strength compared to the Cu-Al-Fe-Ni alloy.

scholarly journals A Comprehensive Study on the Effect of ZnO and ZnAl2O4 Nanoparticles on the Mechanical Properties of Epoxy Coating: Tensile and Hardness

2021 ◽  
Vol 15 (5) ◽  
pp. 45
Author(s):  
Abeer Shmait ◽  
Nour El Ghouch ◽  
J. Al Boukhari ◽  
A. M. Abdel-Gaber ◽  
R. Awad
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Fourier Transform Infrared Spectroscopy ◽  
Fourier Transform Infrared ◽  
Tensile Tests ◽  
Precipitation Method ◽  
Zno Nps ◽  
Co Precipitation

ZnO and ZnAl2O4 nanoparticles (NPs) were successfully prepared by the co-precipitation method and characterized by x-ray powder diffraction, transmission electron microscopy, and Fourier transform infrared spectroscopy. The prepared NPs were incorporated into epoxy (EP) coating with mass ratios 200  800 mg/kg of ZnO NPs/EP and ZnAl2O4 NPs /EP. The prepared coatings were characterized by scanning electron microscopy and Fourier transform infrared spectroscopy, and their mechanical properties were investigated, at room temperature, after 5, 10, 15, and 20 days of preparation. Tensile tests showed an improvement in the tensile properties, with the best improvement in ultimate tensile strength (93.2%) for 800 mg/kg ZnAl2O4 NPs/EP coating after 15 days of preparation. The ZnO NPs/EP and ZnAl2O4 NPs/EP coatings exhibited noticeable sensitivity to the stretching rate. Vickers microhardness (Hv) investigations showed normal indentation size effect behavior for all the samples. The best improvement in Hv was attained after 5 days of preparation, for all coatings, with the best improvement (9.15%) for 700 mg/kg ZnO NPs/EP.

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