High-temperature diffusion annealing process of GH4738 alloy

doi:10.13251/j.issn.0254-6051.2020.10.010

Abstract

Abstract: Equilibrium solidification phase diagram of GH 4738 superalloy was calculated by using Thermal-calc software, based on which experimental parameters of homogenization treatment was established.The segregation of as-cast GH4738 superalloy was observed by using OM and SEM ,the laws of element segregation in the as-cast alloy with as-cast and different diffused annealing state at different temperatures were studied by using EPMA technique.The results show that Ti element segregation is the most serious in the as-cast alloy, the segregation of Ti element is significantly improved after the alloy treated by high-temperature diffusion annealing process, and the effect is the most significant after annealing at 1200 ℃ for 50 h. Meanwhile, the change curves of the residual segregation index versus temperature is calculated, and the calculated results are basically in accord with the experimental results.

Key words: GH4738 alloy, element segregation, diffusion annealing, EPMA

CLC Number:

TG132.3

Su Xing, Shi Songyi, Lü Xudong. High-temperature diffusion annealing process of GH4738 alloy[J]. Heat Treatment of Metals, 2020, 45(10): 48-53.

References

[1]Kelekanjeri V S K G, Gerhardt R A. Characterization of microstructural fluctuations in Waspaloy exposed to 760 ℃ for times up to 2500 h[J]. Electrochimica Acta, 2006, 51(8): 1873-1880.
[2]曲敬龙, 毕中南, 唐超, 等. 航空发动机用优质GH4738合金盘锻件研制进展[C]//第十三届中国高温合金年会摘要文集. 中国金属学会, 2015: 70.
[3]董建新, 丁利生, 王振德. 烟气轮机涡轮盘和叶片用WASPALOY合金研究[J]. 中国材料科技与设备, 2006, 3(2): 68-73.
Dong Jianxin, Ding Lisheng, Wang Zhende. WASPALOY alloy was used to study turbine disk and blade of smoke turbine[J]. China Materials Science, Technology and Equipment, 2006, 3(2): 68-73.
[4]荣义, 成磊, 唐超, 等. 固溶冷却介质对优质GH738合金组织及力学性能的影响[J]. 钢铁研究学报, 2016(28): 74-78.
Rong Yi, Cheng Lei, Tang Chao, et al. Effects of cooling mediums for solution treatment on the microstructure and mechanical properties of high quality GH738 alloy[J]. Journal of Iron and Steel Research, 2016(28): 74-78.
[5]田玉亮, 王玲, 董建新, 等. 均匀化处理过程中Waspaloy合金铸锭中元素分配规律的研究[J]. 稀有金属材料与工程, 2006, 35(9): 1412-1417.
Tian Yuliang, Wang Ling, Dong Jianxin, et al. Investigation on element distribution in Waspaloy alloy Ingot during homogenization[J]. Rare Metal Materials and Engineering, 2006, 35(9): 1412-1417.
[6]缪竹骏. IN718系列高温合金凝固偏析及均匀化处理工艺研究[D]. 上海: 上海交通大学, 2011.
Miao Zhujun. Study on solidification segregation and homogenization treatment of IN718-type superalloys[D]. Shanghai: Shanghai Jiao Tong University, 2011.
[7]杜金辉. Nb、P对GH4169合金凝固行为和性能的影响规律及机制[D]. 北京: 钢铁研究总院, 2015.
Du Jinhui. Study on the effect and mechanism of Nb, P on the solidification behavior and properties of GH4169 alloy[D]. Beijing: Central Iron & Steel Reserch Institute, 2015.
[8]董建新. 高温合金GH4738合金及应用[M]. 北京: 冶金工业出版社, 2014: 47-48.
[9]Semiatin S L, Kramb R C, Turner R E, et al. Analysis of the homogenization of a nickel-base superalloy[J]. Scripta Materialia, 2004, 51(6): 491-495.
[10]Malara Carlo, Radavich John. Alloy 718 large ingots studies[C]//Sixth Internatonal Symposium on Superalloys 718, 625, 706 and Derivatives. Warrendale: TMS, 2005: 25-33.
[11]李浩宇, 董建新, 李林翰. GH4738合金均匀化过程组织演变及热变形行为[J]. 材料热处理学报, 2017, 38(3): 61-69.
Li Haoyu, Dong Jianxin, Li Linhan. Evolution of microstructure and hot deformation behavior of GH4738 alloy during homogenization[J]. Transactions of Materials and Heat Treatment, 2017, 38(3): 61-69.
[12]莫燕, 王东哲, 蒋斌, 等. 钒微合金化对718合金中铌元素偏析行为的影响[J]. 金属热处理, 2017, 42(4): 37-41.
Mo Yan, Wang Dongzhe, Jiang Bin, et al. Effect of microalloying vanadium on micro-segregation behavior of niobium in 718 alloy[J]. Heat Treatment of Metals, 2017, 42(4): 37-41.
[13]顾林喻, 刘忠元, 史正兴. 高梯度快速定向凝固下DZ22高温合金的显微偏析[J]. 中国有色金属学报, 1996, 6(2): 112-115.
Gu Linyu, Liu Zhongyuan, Shi Zhengxing. Microsegregation of DZ22 superalloy unidirectional solidification with high temperature gradient and rapid growth rate[J]. The Chinese Journal of Nonferrous Metals, 1996, 6(2): 112-115.
[14]李红梅, 聂义宏, 朱怀沈, 等. 改型IN617合金大锭型的铸态组织及均匀化工艺[J]. 金属热处理, 2019, 44(10): 105-111.
Li Hongmei, Nie Yihong, Zhu Huaishen, et al. As-cast microstructure and homogenization process of large-scale ingots of modified IN617 superalloy[J]. Heat Treatment of Metals, 2019, 44(10): 105-111.
[15]王南海, 易丹青, 王海生, 等. Al-4.5Cu-3.5Zn-0.5Mg铸造铝合金的均匀化工艺及组织演变[J]. 金属热处理, 2020, 45(1): 174-180.
Wang Nanhai, Yi Danqing, Wang Haisheng, et al. Homogenization process and microstructure evolution of Al-4.5Cu-3.5Zn-0.5Mg as-cast alloy[J]. Heat Treatment of Metals, 2020, 45(1): 174-180.
[16]陈涛, 王福明, 郭军, 等. MG600钢凝固过程中的微观偏析和成分均匀化[J]. 金属热处理, 2017, 42(10): 179-184.
Chen Tao, Wang Fuming, Guo Jun, et al. Micro-segregation and composition homogenization of MG600 steel during solidification[J]. Heat Treatment of Metals, 2017, 42(10): 179-184.
[17]苏瑞平. GH864合金γ′和晶界碳化物演变规律及均匀化机制[D]. 北京: 北京科技大学, 2009.
Su Ruiping. Evolution of γ′ precipitates and grain boundary carbides at high temperature and homogenization mechanism for a Ni-base superalloy GH864[D]. Beijing: University of Science and Technology Beijing, 2009.