Morphological Evolution of Carbides in DZ125 Superalloy during Heat Treatment

2016 ◽  
Vol 879 ◽  
pp. 1153-1158
Author(s):  
Li Rong Liu ◽  
Shuo Han ◽  
Yi Fan Pu ◽  
Zhi Jiang Peng ◽  
Ming Jun Zhang

Morphological evolution of carbides in DZ125 superalloy during heat treatment was investigated by using SEM and EDS. The results show that in DZ125 directionally solidified superalloy, the MC carbide is either smooth platelet or bone-shaped structure with nodes in morphology in as-cast state, which is rich in Ta, Ti and Hf. During solid solution treatment, parts of primary MC carbides dissolve, so that the morphology of MC carbide changes from smooth and regular surface to scattered configuration. During aging heat treatment and long term aging, the secondary MC carbides enriched in Hf element precipitated from the matrix. Moreover, there is some M6C carbide enriched in W element precipitated on the grain boundary. With the process of heat treatment, the content of Hf element in MC carbides increases obviously.

2021 ◽  
Vol 1023 ◽  
pp. 45-52
Author(s):  
Xiao Yan Wang ◽  
Meng Li ◽  
Zhi Xun Wen

After solid solution treatment at 1335°C for 4 hours and cooling to room temperature at different rate, the nickel-based single crystal superalloy were made into three kinds of nickel-based single crystal superalloy materials containing different size γ′ phases, respectively. The tensile test of I-shaped specimens was carried out at 980°C, and their effect of γ′ phase microstructure on the tensile properties was studied. The results show that the yielding strength of the material air-cooled to room temperature was lower than that with cooling rate at 0.15°C/s, but both of them were lower than the yielding strength of original material. Little difference was found on the elastic modulus of I-shaped specimens made of three kinds of materials. When the cubic degree of the γ′ phase is higher and the size is larger, the tensile properties of the material is better, which can be attributed to the larger size and narrower channel of the matrix phase that lead to higher dislocation resistance.


2011 ◽  
Vol 378-379 ◽  
pp. 744-747 ◽  
Author(s):  
Jeong Min Kim ◽  
Joon Sik Park ◽  
Ho Seob Yun ◽  
Seung Jin Lee ◽  
Seong Uk An

Cast IN738LC alloy mainly consists of primary gamma matrix, gamma prime precipitates, and carbides. SEM-EDS analysis results suggested that most of the carbides are MC type ones that possess high Ti or Ta contents. MC carbides were partly dissolved into the matrix during the solid solution treatment, and the morphology and size of carbides were influenced by the solid solution treatment temperature. Characteristics of gamma prime precipitates were also significantly affected by the solid solution treatment conditions. Single or duplex size distributions of gamma prime precipitates were obtained depending on the solid solution treatment condition. Higher tensile strength was obtained in the case of finer precipitation size and in the case of single size distribution as compared with that of duplex size distribution.


2005 ◽  
Vol 297-300 ◽  
pp. 1220-1222
Author(s):  
Shi Chang Cheng ◽  
Zhao Jie Lin ◽  
Gang Yang ◽  
Zheng Dong Liu

The authors experimentally investigated the change of mechanical properties of Inconel X-750 alloy under various heat treatments. For the selected specimens, solid solution treatment under different temperatures was carried out, followed air cooling or furnace cooling. Results show that suitable solid solution treatment and air cooling enhances the strength, plasticity, impact toughness at room temperature of the alloy and lowers the hardness of the alloy at room temperature.


2014 ◽  
Vol 988 ◽  
pp. 145-150
Author(s):  
Jian Chen ◽  
Ming Zhang ◽  
Dong Yang ◽  
Huan Liang

CuNiCoBe alloy and CuCoBe alloy were cast by the vacuum inductive melting technique, and were heat treated under certain parameters. By using optical microscope, sclerometer and conductivity meter, the properties of two alloys were investigated after heat treatment. Experimental results show that the process of 980 °C for solid solution and three hours of aging at 450 °C is the best heat treatment for CuCoBe alloy, while 960 °C is the best solid solution treatment temperature for CuNiCoBe alloy with the same aging measures. Ni is beneficial to improve the hardness and conductivity of alloys, and CuNiCoBe alloy has better strength, hardness and conductivity than CuCoBe alloy at different temperatures, and two alloys all have a conductivity mutation increase near 450 °C. CuNiCoBe alloy and CuCoBe alloy soften respectively at 464 °C and 471 °C.


2011 ◽  
Vol 194-196 ◽  
pp. 1319-1325
Author(s):  
Zheng Tian ◽  
Zhan Yi Cao ◽  
Jian Meng

The effect of yttrium addition and heat treatment on the mechanical properties and microstructure of AM60 magnesium alloy have been investigated using X-ray phase analysis, microstructure investigation, tensile test, hardness measurement and fracture surfaces analysis. The results showed that the mechanical properties of the alloys were obviously improved with the addition of yttrium no more than 1.0%. The reinforcement of the alloys resulted from the appearance of Al2Y phase. After solid-solution treatment (T4), the Mg17Al12 phase almost dissolved in Mg matrix, but the rare earth compounds Al2Y phase was rather stable. The ultimate tensile strength σb was improved, but the yield strength σ0.2 and elongation δ were only slightly changed. After solid-solution + aging treatment (T6), the Mg17Al12 phase precipitated again and their morphology was changed. The yield strength σ0.2 was improved.


In this work, ZA-27 alloy was fabricated and solid solution treatment at 120, 240 and 360 °C for 1 hr., microstructure and physical properties of alloy were studied by X-ray diffraction, scanning electron microscopy. Results observed that the microstructure of ZA-27 alloy manufactured (as-cast) was composed of α, β, η and ε phases, then decomposed to β phase at 360 oC. The heat treatment of ZA-27 alloys influenced on microstructure, decreasing of strength and hardness, but also causes increasing of elongation. The wear rates of changes increase with increasing solid solution treatment


2015 ◽  
Vol 816 ◽  
pp. 446-450
Author(s):  
Xiao Bing Zheng ◽  
Wen Bo Du ◽  
Ke Liu ◽  
Zhao Hui Wang ◽  
Shu Bo Li

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.


Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 688
Author(s):  
Zhi-Fa Wang ◽  
Tian-Jing Miao ◽  
Shu-Qing Kou ◽  
Shuang Zhang ◽  
Feng Qiu

An experimental investigation was carried out to study the effects of solid solution treatment and aging treatment on the microstructures and mechanical properties of an Al-13Si-5Cu-2Ni alloy. The results show that the size of eutectic silicon decreased with solid solution treatment temperature increasing until 510 °C. Subsequently, the eutectic silicon size continued to increase as the temperature increased to 520 °C. Initially, the acicular eutectic silicon of the as-cast alloy was 10.1 μm in size. After the solid solution treatment at 510 °C, the eutectic silicon size was reduced to 6.5 μm. The θ′ phase is the main strengthening phase in the alloy, therefore, the effect of aging treatment on θ′ phases was explored. As the aging time increased, the diameter, length, and fraction volume of the θ′ phases were found to increase. The main reason for the improved performance of this alloy following heat treatment is the passivation spheroidization of the silicon phase and Orowan strengthening due to the θ′ phases. The optimal tensile strength of an Al-13Si-5Cu-2Ni alloy was obtained after solid solution treatment at 510 °C for 8 h followed by an aging treatment at 165 °C for 8 h. Therefore, this work has great significance for promoting the application of Al alloys at high temperatures.


2005 ◽  
Vol 488-489 ◽  
pp. 257-260 ◽  
Author(s):  
Jianguo Peng ◽  
Qu Dong Wang ◽  
Man Ping Liu ◽  
Yongjun Chen ◽  
Wen Jiang Ding ◽  
...  

Effects of solution and aging treatment on microstructure and mechanical properties of rolled AM50+xCa alloys(x=0, 1, 2 wt. %) were studied. The results indicated that, with increasing solution time i, the secondary phase Mg17Al12 was dissolved into the Mg matrix and Al2Ca became thinner and shorter, then gradually broken and spheroidized.With an increase of aging time, Mg17Al12 precipitated from the Mg matrix in the form of particles and Al2Ca changed a little. After solution treatment, hardness and tensile properties of the alloy’s decreased. After the aging treatment, the alloy’s hardness increased first and decreased later while the tensile properties increased little. The solution and aging treatment can increase the ductility of AM50 and AM50+1Ca alloys. For AM50+2Ca alloy, the ductility increased after solid solution treatment and decreased after aging treatment.


2014 ◽  
Vol 1035 ◽  
pp. 272-276
Author(s):  
Run Xia Li ◽  
Qing Li ◽  
Yan Jiao Tong ◽  
Xin Ying Luan ◽  
Zhe Liu ◽  
...  

The effect of heat treatment process on the microstructure and properties of casting Al-5.5Fe-4Cu-2Zn-0.4Mg-0.5Mn alloy were studied. It has been founded that, the mechanicals properties of casting Al-5.5Fe-4Cu-2Zn-0.4Mg-0.5Mn alloy improved significantly after solid solution and aging treated (T6), the tensile strength increased from 173.4MPa to 218.7 MPa. However the mechanical properties of the alloy after aging treated (T1) get less enhanced and the tensile strength only achieved 194.07MPa. The SEM and TEM analysis shows that solid solution treatment plays a role of dissolving the second phases in casting Al-5.5Fe-4Cu-2Zn-0.4Mg-0.5Mn alloy. After solution treatment the alloy was proceed with low-temperature ageing treatment, a large number of dispersively tiny phases precipitated in the matrix of the alloy, which exhibits strengthening action.


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