Cold Metal Transfer （CMT） welding technique is a new welding technique introduced by Fronins company. CMT welding of nickel-based alloy with stainless steel was carried out using CuSi3 filler wire in this paper. Eff...Cold Metal Transfer （CMT） welding technique is a new welding technique introduced by Fronins company. CMT welding of nickel-based alloy with stainless steel was carried out using CuSi3 filler wire in this paper. Effects of welding parameters, including welding current, welding speed, etc, on weld surface appearance were tested. Microstructure and mechanical properties of CMT weld were studied. The results shaw that the thickness of interface reaction layer of the nickel- based alloy is 14. 3 μm, which is only 4. 33% of base material. The weld is made up of two phases, α-copper and iron-based solid solution. Rupture occurs initially at the welded seam near the edge of stainless steel in shear test. The maximum shear strength of the CuSi3 welded joint is 184. 9 MPa.展开更多
A quantitative relation between the γ/γ′ and γ/Laves intermetallics was investigated with the change of chemical composition, i.e., Ti, Al and Nb in the third generation of nickel-based superalloys. The ...A quantitative relation between the γ/γ′ and γ/Laves intermetallics was investigated with the change of chemical composition, i.e., Ti, Al and Nb in the third generation of nickel-based superalloys. The results demonstrated that the maximum amount of intermetallic eutectics （i.e., 41.5%, mass fraction） has been formed in 9.8% （Ti＋Al）. It is predicted that high level of intermetallics formed in the 3GSA-HNM-1 （γ-9.8%（Ti＋Al）） deteriorates its castability. The type and morphology of eutectic intermetallics change and the amount considerably diminishes by decreasing Ti＋Al in 3GSA-HNM-2 （γ-7.6%（Ti＋Al）, 1.5% Nb）. Thus, it is predicted that the castability for the 3GSA-HNM-2 improves. The amount of Laves intermetallics shows an ascending behavior again, however, with less intensity by increasing the Nb content in the 3GSA-HNM-3 （γ-5.7%（Ti＋Al）, 2.9% Nb）. It can be concluded that for 3GSA-HNM-3 with composition of γ-5.7%（Ti＋Al） and 2.9% Nb, the optimized castability can be anticipated, because the minimum amount of eutectic intermetallics （i.e., 4.7%） is formed.展开更多
The synergistic damage effect of irradiation and corrosion of reactor structural materials has been a prominent research focus.This paper provides a comprehensive review of the synergistic effects on the third-and fou...The synergistic damage effect of irradiation and corrosion of reactor structural materials has been a prominent research focus.This paper provides a comprehensive review of the synergistic effects on the third-and fourth-generation fission nuclear energy structural materials used in pressurized water reactors and molten salt reactors.The competitive mechanisms of multiple influencing factors,such as the irradiation dose,corrosion type,and environmental temperature,are summarized in this paper.Conceptual approaches are proposed to alleviate the synergistic damage caused by irradiation and corrosion,thereby promoting in-depth research in the future and solving this key challenge for the structural materials used in reactors.展开更多
In order to obtain good understanding of complicated beam propagation behaviors in nickel-based alloy weldments , ray tracing simulation is established to predict the ultrasonic beam path in a special welded structure...In order to obtain good understanding of complicated beam propagation behaviors in nickel-based alloy weldments , ray tracing simulation is established to predict the ultrasonic beam path in a special welded structure of dissimilar steels. Also experimental examinations are carried out to measure the ultrasonic beam paths in the weldment. Then comparisons of the modeling predictions with experimental results are presented to reveal the complicated beam propagation behaviors.展开更多
Chromia-forming alloys have good resistance to oxidizing agents such as O2, CO2, … It is accepted that the protection of these alloys is always due to the chromia layer formed at the surface of the alloys, which acts...Chromia-forming alloys have good resistance to oxidizing agents such as O2, CO2, … It is accepted that the protection of these alloys is always due to the chromia layer formed at the surface of the alloys, which acts as a barrier between the oxidizing gases and the alloy substrates, forming a diffusion zone that limits the overall reaction rate and leads to parabolic kinetics. But this was not verified in the study devoted to Inconel®625 the oxidation in CO2 that was followed by TGA, with characterizations by XRD, EDS and FIB microscopy. Contrary to what was expected and accepted in similar studies on other chromia-forming alloys, it was shown that the diffusion step that governs the overall reaction rate is not located inside the chromia layer but inside the alloy, precisely inside a zone just beneath the interface alloy/chromia, this zone being depleted in chromium. The chromia layer, therefore, plays no kinetic role and does not directly protect the underlying alloy. This result was demonstrated using a simple test that consisted in removing the chromia layer from the surface of samples partially oxidized and then to continue the thermal treatment: insofar as the kinetics continued without any change in rate, this proved that this surface layer of oxide did not protect the substrate. Based on previous work on many chromia-forming alloys, the possibility of a similar reaction mechanism is discussed. If the chromia layer is not the source of protection for a number of chromia-forming alloys, as is suspected, this might have major consequences in terms of industrial applications.展开更多
Nickel-based alloys have been considered as candidate structural materials used in generation IV nuclear reactors serving at high temperatures.In the present study,alloy 617 was irradiated with 180-keV helium ions to ...Nickel-based alloys have been considered as candidate structural materials used in generation IV nuclear reactors serving at high temperatures.In the present study,alloy 617 was irradiated with 180-keV helium ions to a fluence of 3.6×10^(17) ions/cm^(2) at room temperature.Throughout the cross-section transmission electron microscopy(TEM)image,numerous over-pressurized helium bubbles in spherical shape are observed with the actual concentration profile a little deeper than the SRIM predicted result.Post-implantation annealing was conducted at 700℃for 2 h to investigate the bubble evolution.The long-range migration of helium bubbles occurred during the annealing process,which makes the bubbles of the peak region transform into a faceted shape as well.Then the coarsening mechanism of helium bubbles at different depths is discussed and related to the migration and coalescence(MC)mechanism.With the diffusion of nickel atoms slowed down by the alloy elements,the migration and coalescence of bubbles are suppressed in alloy 617,leading to a better helium irradiation resistance.展开更多
The electronic properties of passive films formed on G3 and G30 alloys in bicarbonate/carbonate buffer solution were comparatively studied by electrochemical impedance spectra（EIS） and Mott-Schottky analysis, the ch...The electronic properties of passive films formed on G3 and G30 alloys in bicarbonate/carbonate buffer solution were comparatively studied by electrochemical impedance spectra（EIS） and Mott-Schottky analysis, the chemical composition of the passive film formed on G3 alloy was detected by X-ray photoelectron spectroscopy （XPS）. The results show that passive film on G3 alloy had better protection than that on G30 alloy. The transfer resistance, film resistance and diffusion resistance of the passive films on both alloys increased with increasing formation potential, prolonging formation time, increasing pH value, decreasing formation temperature, and decreasing chloride and sulphide ions concentration. Mott-Schottky plot reveals that the passive films on the two alloys show a p-n semi-conductive character. XPS analysis indicates that the passive film on G3 alloy was composed of an inner Cr oxide and an outer Fe, Mo/Ni oxides.展开更多
The use of high-temperature materials is especially important in power station construction, heating systems engineering, furnace industry, chemical and petrochemical industry, waste incineration plants, coal gasifica...The use of high-temperature materials is especially important in power station construction, heating systems engineering, furnace industry, chemical and petrochemical industry, waste incineration plants, coal gasification plants and for flying gas turbines in civil and military aircrafts and helicopters. Particularly in recent years, the development of new processes and the drive to improve the economics of existing processes have increased the requirements significantly so that it is necessary to change from well-proven materials to new alloys. Hitherto, heat resistant ferritic steels sufficed in conventional power station constructions for temperatures up to 550℃ newly developed ferritic/martensitic steels provide sufficient strength up to about 600 - 620℃. In new processes, e.g. fluidized-bed combustion of coal, process temperatures up to 900℃ occur. However, this is not the upper limit, since in combustion engines, e.g. gas turbines. Material temperatures up to 1100℃ are reached locally. Similar development trends can also be identified in the petrochemical industry and in the heat treatment and furnace engineering. The advance to ever higher material temperatures now not only has the consequence of having to use materials with enhanced high-strength properties, considerable attention now also has to be given to their chemical stability in corrosive media. Therefore not only examples of the use of high-temperature alloys for practical applications will be given but also be contributed to some general rules for material selection with regard to their high-temperature strength and corrosion resistance.展开更多
The role of niobium in nickel-based superalloys is reviewed. The importance of niobium as a strengthener is discussed. New developments in nickel-based superalloys are also briefly mentioned, including some results th...The role of niobium in nickel-based superalloys is reviewed. The importance of niobium as a strengthener is discussed. New developments in nickel-based superalloys are also briefly mentioned, including some results that show improved resistance to sulfidation by niobium. Research results from a current program on the role of niobium in the Russian powder metallurgy alloy EP741NP are presented. Future research plans on the role of niobium in superalloys are also discussed.展开更多
This paper introduces a thick 690 nickel-based alloy plate produced by the former Baosteel Special Steel Co.,Ltd.used as the steam-generator divider plate in the pressurized water reactor nuclear power plant.According...This paper introduces a thick 690 nickel-based alloy plate produced by the former Baosteel Special Steel Co.,Ltd.used as the steam-generator divider plate in the pressurized water reactor nuclear power plant.According to the product characteristics and design requirements of the thick nickel-based alloy plate,multidimensional sampling and testing were conducted to investigate its microstructure and mechanical properties.The results show that all the property indexes of the thick hot-rolled nickel-based alloy plate meet the design requirements,and there is good uniformity in the microstructure and mechanical properties in different dimensions.These findings indicate that China has mastered the core manufacturing technology of thick nickel-based alloy plates for their use as divider plates in nuclear power steam generators.展开更多
The sulfide stress corrosion cracking（ SSC） performance of G3 and 028 nickel-based alloys w as studied using slow strain rate test（ SSRT） and the four-point bend（ FPB） test under simulated dow nhole conditions. ...The sulfide stress corrosion cracking（ SSC） performance of G3 and 028 nickel-based alloys w as studied using slow strain rate test（ SSRT） and the four-point bend（ FPB） test under simulated dow nhole conditions. The effect of high temperature,high H2 S / CO2 partial pressure,and the presence of sulfur on SSC susceptibility w as investigated. The G3 alloy w as found to have a higher SSC resistance than the 028 alloy. Presence of sulfur and temperature bear a strong influence on the SSC performance of the metals,particularly on the 028 alloy. The applicability of 028 and G3 alloys may be expanded and both could safely be used beyond the limits set by the ISO15156-3 standard.展开更多
Precipitation in Inconel 625 alloy has been studied by positron annihilation spectroscopy and electron microscopy. The observed dependence of annihilation characteristics on aging time is attributed to the change of t...Precipitation in Inconel 625 alloy has been studied by positron annihilation spectroscopy and electron microscopy. The observed dependence of annihilation characteristics on aging time is attributed to the change of the positron state due to the increase and decrease of the density and size of the 7' precipitates. Hardness measurements and lifetime measurements are in good agreement.展开更多
The formation mechanism and wear behavior of a gradient nanostructured(GNS) Inconel 625 alloy were investigated using SEM, TEM and ball-on-disc sliding wear tester. The results show that surface mechanical grinding tr...The formation mechanism and wear behavior of a gradient nanostructured(GNS) Inconel 625 alloy were investigated using SEM, TEM and ball-on-disc sliding wear tester. The results show that surface mechanical grinding treatment(SMGT) induced an approximately 800 μm-deep gradient microstructure, consisting of surface nano-grained,nano-laminated, nano-twined, and severely deformed layers, which resulted in a reduced gradient in micro-hardness from 6.95 GPa(topmost surface) to 2.77 GPa(coarse-grained matrix). The nano-grained layer resulted from the formation of high-density nano-twins and subsequent interaction between nano-twins and dislocations. The width and depth of the wear scar, wear loss volume, and wear rate of the SMGT-treated sample were smaller than those of untreated coarse-grained sample. Moreover, the wear mechanisms for both samples were mainly abrasive wear and adhesive wear, accompanied with mild oxidation wear. The notable wear resistance enhancement of the GNS Inconel 625 alloy was attributed to the high micro-hardness, high residual compressive stress, and high strain capacity of the GNS surface layer.展开更多
Effects of solution treatment between 1050 and 1250℃on microstructure and tensile properties of as-cast alloy 625 were investigated.The microstructure and solidification characteristics of the alloy were studied by S...Effects of solution treatment between 1050 and 1250℃on microstructure and tensile properties of as-cast alloy 625 were investigated.The microstructure and solidification characteristics of the alloy were studied by SEM,EDS,EPMA and DTA.The results showed that the solidification sequence of the alloy should be written as L→L+γ→L+γ+MC→L+γ+MC+γ/Laves→γ+MC+γ/Laves.After solution treatment at 1225 and 1250°C,incipient melting of Laves phase was observed.The ultimate tensile strength decreased monotonically with the increase of solution treatment temperature,and the yield strength had no significant variation.The elongation increased slightly at first and then reached a minimum value at 1250°C.The fracture mechanism changed from transgranular mode to intergranular mode after solution at 1250°C for the reason that numerous Laves phases melted at grain boundaries and microcracks nucleated in the molten pool.The suitable solution treatment temperature of this alloy was 1200°C.展开更多
文摘Cold Metal Transfer （CMT） welding technique is a new welding technique introduced by Fronins company. CMT welding of nickel-based alloy with stainless steel was carried out using CuSi3 filler wire in this paper. Effects of welding parameters, including welding current, welding speed, etc, on weld surface appearance were tested. Microstructure and mechanical properties of CMT weld were studied. The results shaw that the thickness of interface reaction layer of the nickel- based alloy is 14. 3 μm, which is only 4. 33% of base material. The weld is made up of two phases, α-copper and iron-based solid solution. Rupture occurs initially at the welded seam near the edge of stainless steel in shear test. The maximum shear strength of the CuSi3 welded joint is 184. 9 MPa.
文摘A quantitative relation between the γ/γ′ and γ/Laves intermetallics was investigated with the change of chemical composition, i.e., Ti, Al and Nb in the third generation of nickel-based superalloys. The results demonstrated that the maximum amount of intermetallic eutectics （i.e., 41.5%, mass fraction） has been formed in 9.8% （Ti＋Al）. It is predicted that high level of intermetallics formed in the 3GSA-HNM-1 （γ-9.8%（Ti＋Al）） deteriorates its castability. The type and morphology of eutectic intermetallics change and the amount considerably diminishes by decreasing Ti＋Al in 3GSA-HNM-2 （γ-7.6%（Ti＋Al）, 1.5% Nb）. Thus, it is predicted that the castability for the 3GSA-HNM-2 improves. The amount of Laves intermetallics shows an ascending behavior again, however, with less intensity by increasing the Nb content in the 3GSA-HNM-3 （γ-5.7%（Ti＋Al）, 2.9% Nb）. It can be concluded that for 3GSA-HNM-3 with composition of γ-5.7%（Ti＋Al） and 2.9% Nb, the optimized castability can be anticipated, because the minimum amount of eutectic intermetallics （i.e., 4.7%） is formed.
基金supported by the National Natural Science Foundation of China(Nos.12022515 and 11975304)the Youth Innovation Promotion Association,Chinese Academy of Sciences(No.Y202063)。
文摘The synergistic damage effect of irradiation and corrosion of reactor structural materials has been a prominent research focus.This paper provides a comprehensive review of the synergistic effects on the third-and fourth-generation fission nuclear energy structural materials used in pressurized water reactors and molten salt reactors.The competitive mechanisms of multiple influencing factors,such as the irradiation dose,corrosion type,and environmental temperature,are summarized in this paper.Conceptual approaches are proposed to alleviate the synergistic damage caused by irradiation and corrosion,thereby promoting in-depth research in the future and solving this key challenge for the structural materials used in reactors.
基金supported by National Natural Science Foundation of China (Grant No. 50775054)International Joint Research Program of China (Grant No. 2007DFR70070)
文摘In order to obtain good understanding of complicated beam propagation behaviors in nickel-based alloy weldments , ray tracing simulation is established to predict the ultrasonic beam path in a special welded structure of dissimilar steels. Also experimental examinations are carried out to measure the ultrasonic beam paths in the weldment. Then comparisons of the modeling predictions with experimental results are presented to reveal the complicated beam propagation behaviors.
文摘Chromia-forming alloys have good resistance to oxidizing agents such as O2, CO2, … It is accepted that the protection of these alloys is always due to the chromia layer formed at the surface of the alloys, which acts as a barrier between the oxidizing gases and the alloy substrates, forming a diffusion zone that limits the overall reaction rate and leads to parabolic kinetics. But this was not verified in the study devoted to Inconel®625 the oxidation in CO2 that was followed by TGA, with characterizations by XRD, EDS and FIB microscopy. Contrary to what was expected and accepted in similar studies on other chromia-forming alloys, it was shown that the diffusion step that governs the overall reaction rate is not located inside the chromia layer but inside the alloy, precisely inside a zone just beneath the interface alloy/chromia, this zone being depleted in chromium. The chromia layer, therefore, plays no kinetic role and does not directly protect the underlying alloy. This result was demonstrated using a simple test that consisted in removing the chromia layer from the surface of samples partially oxidized and then to continue the thermal treatment: insofar as the kinetics continued without any change in rate, this proved that this surface layer of oxide did not protect the substrate. Based on previous work on many chromia-forming alloys, the possibility of a similar reaction mechanism is discussed. If the chromia layer is not the source of protection for a number of chromia-forming alloys, as is suspected, this might have major consequences in terms of industrial applications.
基金Project supported by the Special Funds for the Key Research and Development Program of the Ministry of Science and Technology of China(Grant Nos.2017YFB0702201 and 2020YFB1901800)the National Natural Science Foundation of China(Grant Nos.11975135 and 12005017).
文摘Nickel-based alloys have been considered as candidate structural materials used in generation IV nuclear reactors serving at high temperatures.In the present study,alloy 617 was irradiated with 180-keV helium ions to a fluence of 3.6×10^(17) ions/cm^(2) at room temperature.Throughout the cross-section transmission electron microscopy(TEM)image,numerous over-pressurized helium bubbles in spherical shape are observed with the actual concentration profile a little deeper than the SRIM predicted result.Post-implantation annealing was conducted at 700℃for 2 h to investigate the bubble evolution.The long-range migration of helium bubbles occurred during the annealing process,which makes the bubbles of the peak region transform into a faceted shape as well.Then the coarsening mechanism of helium bubbles at different depths is discussed and related to the migration and coalescence(MC)mechanism.With the diffusion of nickel atoms slowed down by the alloy elements,the migration and coalescence of bubbles are suppressed in alloy 617,leading to a better helium irradiation resistance.
基金Supported by the National Natural Science Foundation of China(Nos.51075228 50721004)
文摘The electronic properties of passive films formed on G3 and G30 alloys in bicarbonate/carbonate buffer solution were comparatively studied by electrochemical impedance spectra（EIS） and Mott-Schottky analysis, the chemical composition of the passive film formed on G3 alloy was detected by X-ray photoelectron spectroscopy （XPS）. The results show that passive film on G3 alloy had better protection than that on G30 alloy. The transfer resistance, film resistance and diffusion resistance of the passive films on both alloys increased with increasing formation potential, prolonging formation time, increasing pH value, decreasing formation temperature, and decreasing chloride and sulphide ions concentration. Mott-Schottky plot reveals that the passive films on the two alloys show a p-n semi-conductive character. XPS analysis indicates that the passive film on G3 alloy was composed of an inner Cr oxide and an outer Fe, Mo/Ni oxides.
文摘The use of high-temperature materials is especially important in power station construction, heating systems engineering, furnace industry, chemical and petrochemical industry, waste incineration plants, coal gasification plants and for flying gas turbines in civil and military aircrafts and helicopters. Particularly in recent years, the development of new processes and the drive to improve the economics of existing processes have increased the requirements significantly so that it is necessary to change from well-proven materials to new alloys. Hitherto, heat resistant ferritic steels sufficed in conventional power station constructions for temperatures up to 550℃ newly developed ferritic/martensitic steels provide sufficient strength up to about 600 - 620℃. In new processes, e.g. fluidized-bed combustion of coal, process temperatures up to 900℃ occur. However, this is not the upper limit, since in combustion engines, e.g. gas turbines. Material temperatures up to 1100℃ are reached locally. Similar development trends can also be identified in the petrochemical industry and in the heat treatment and furnace engineering. The advance to ever higher material temperatures now not only has the consequence of having to use materials with enhanced high-strength properties, considerable attention now also has to be given to their chemical stability in corrosive media. Therefore not only examples of the use of high-temperature alloys for practical applications will be given but also be contributed to some general rules for material selection with regard to their high-temperature strength and corrosion resistance.
文摘The role of niobium in nickel-based superalloys is reviewed. The importance of niobium as a strengthener is discussed. New developments in nickel-based superalloys are also briefly mentioned, including some results that show improved resistance to sulfidation by niobium. Research results from a current program on the role of niobium in the Russian powder metallurgy alloy EP741NP are presented. Future research plans on the role of niobium in superalloys are also discussed.
基金sponsored by Special Fund for Indus-trial Transformation and Upgrading in Shanghai(No.GYQJ-2018-2-03)Program of Shanghai Academ-ic/Technology Research Leader(No.17XD1420200).
文摘This paper introduces a thick 690 nickel-based alloy plate produced by the former Baosteel Special Steel Co.,Ltd.used as the steam-generator divider plate in the pressurized water reactor nuclear power plant.According to the product characteristics and design requirements of the thick nickel-based alloy plate,multidimensional sampling and testing were conducted to investigate its microstructure and mechanical properties.The results show that all the property indexes of the thick hot-rolled nickel-based alloy plate meet the design requirements,and there is good uniformity in the microstructure and mechanical properties in different dimensions.These findings indicate that China has mastered the core manufacturing technology of thick nickel-based alloy plates for their use as divider plates in nuclear power steam generators.
文摘The sulfide stress corrosion cracking（ SSC） performance of G3 and 028 nickel-based alloys w as studied using slow strain rate test（ SSRT） and the four-point bend（ FPB） test under simulated dow nhole conditions. The effect of high temperature,high H2 S / CO2 partial pressure,and the presence of sulfur on SSC susceptibility w as investigated. The G3 alloy w as found to have a higher SSC resistance than the 028 alloy. Presence of sulfur and temperature bear a strong influence on the SSC performance of the metals,particularly on the 028 alloy. The applicability of 028 and G3 alloys may be expanded and both could safely be used beyond the limits set by the ISO15156-3 standard.
文摘Precipitation in Inconel 625 alloy has been studied by positron annihilation spectroscopy and electron microscopy. The observed dependence of annihilation characteristics on aging time is attributed to the change of the positron state due to the increase and decrease of the density and size of the 7' precipitates. Hardness measurements and lifetime measurements are in good agreement.
基金financially supported by the National Key Research and Development Program of China (No. 2017YFA07007003)the National Natural Science Foundation of China (No. 51661019)+4 种基金the Program for Major Projects of Science and Technology in Gansu Province, China (No. 145RTSA004)the Hongliu First-class Discipline Construction Plan of Lanzhou University of Technology, Chinathe Incubation Program of Excellent Doctoral Dissertation, Lanzhou University of Technology, Chinathe Lanzhou University of Technology Excellent Students Studying Abroad Learning Exchange Fundthe State Key Laboratory of Cooperation and Exchange Fund。
文摘The formation mechanism and wear behavior of a gradient nanostructured(GNS) Inconel 625 alloy were investigated using SEM, TEM and ball-on-disc sliding wear tester. The results show that surface mechanical grinding treatment(SMGT) induced an approximately 800 μm-deep gradient microstructure, consisting of surface nano-grained,nano-laminated, nano-twined, and severely deformed layers, which resulted in a reduced gradient in micro-hardness from 6.95 GPa(topmost surface) to 2.77 GPa(coarse-grained matrix). The nano-grained layer resulted from the formation of high-density nano-twins and subsequent interaction between nano-twins and dislocations. The width and depth of the wear scar, wear loss volume, and wear rate of the SMGT-treated sample were smaller than those of untreated coarse-grained sample. Moreover, the wear mechanisms for both samples were mainly abrasive wear and adhesive wear, accompanied with mild oxidation wear. The notable wear resistance enhancement of the GNS Inconel 625 alloy was attributed to the high micro-hardness, high residual compressive stress, and high strain capacity of the GNS surface layer.
基金the financial support from the National Natural Science Foundation of China (51571191)
文摘Effects of solution treatment between 1050 and 1250℃on microstructure and tensile properties of as-cast alloy 625 were investigated.The microstructure and solidification characteristics of the alloy were studied by SEM,EDS,EPMA and DTA.The results showed that the solidification sequence of the alloy should be written as L→L+γ→L+γ+MC→L+γ+MC+γ/Laves→γ+MC+γ/Laves.After solution treatment at 1225 and 1250°C,incipient melting of Laves phase was observed.The ultimate tensile strength decreased monotonically with the increase of solution treatment temperature,and the yield strength had no significant variation.The elongation increased slightly at first and then reached a minimum value at 1250°C.The fracture mechanism changed from transgranular mode to intergranular mode after solution at 1250°C for the reason that numerous Laves phases melted at grain boundaries and microcracks nucleated in the molten pool.The suitable solution treatment temperature of this alloy was 1200°C.
