Dynamic Softening Mechanisms of GH4720Li AlloyDuring Hot Deformation

doi:10.11900/0412.1961.2018.00179

Acta Metall Sin

2019, Vol. 55

Issue (2): 213-222 DOI: 10.11900/0412.1961.2018.00179

Orginal Article

Current Issue | Archive | Adv Search

Dynamic Softening Mechanisms of GH4720Li AlloyDuring Hot Deformation

Zhipeng WAN^1,²(

), Tao WANG¹, Yu SUN², Lianxi HU², Zhao LI¹, Peihuan LI¹, Yong ZHANG¹

1 Science and Technology on Advanced High Temperature Structural Materials Laboratory, AEEC Beijing Institute of Aeronautical Materials, Beijing 100095, China
2 National Key Laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin 150001, China

Cite this article:

Zhipeng WAN, Tao WANG, Yu SUN, Lianxi HU, Zhao LI, Peihuan LI, Yong ZHANG. Dynamic Softening Mechanisms of GH4720Li AlloyDuring Hot Deformation. Acta Metall Sin, 2019, 55(2): 213-222.

Download:

HTML

PDF(16376KB)
Export: BibTeX | EndNote (RIS)

Abstract

GH4720Li alloy is a precipitation strengthened Ni-based superalloy and widely applied in high performance applications such as disks and blades of either aircraft engines or land-based gas turbines attributing to its excellent properties including resistance to creep and fatigue, together with corrosion, fracture and microstructural stability for the intended applications. Hot working is an effective way for shaping metals and alloys as well as changing the microstructure and mechanical properties. Lots of typical metallurgical behaviors such as dynamic recovery (DRV), discontinuous dynamic recrystallization (DDRX) and continuous dynamic recrystallization (CDRX) occur, which are related to the hot working parameters, including deformation temperature, strain rate and strain. In order to investigate the effect of deformation parameters on dynamic softening behavior and evolution of twinning for GH4720Li alloy, the hot deformation behavior of as-forged GH4720Li alloy was studied by isothermal compression tests. OM, SEM, EBSD and TEM techniques were employed to investigate systematically the dynamic softening mechanisms, formation of DRX grains and evolution of substructure in grains under different deformation parameters. The results showed that DDRX can take place at all studied deformation conditions. The boundary bulging and nucleation of DDRX grains were restrained as a result of decrease of dislocation substructures and subgrain boundaries density consumed by continuous original boundary migration (COBM) in deformed grains at low strain rates and high temperatures, and then the occurrence of DDRX was suppressed. DDRX was promoted as the strain rate was increased and uniform microstructures composed of fine equiaxed grains can be readily obtained as well. The microstructural changes showed that the pinning effect of fine undissolved γ' precipitates was able to hinder the dislocation movement and promote the formation of high density of dislocation substructures and subgrain boundaries in deformed grains. The increase in sub-boundary misorientation brought about by continuous accumulation of the dislocations was introduced by the deformation, and fine DRX grains formed by particle-induced continuous dynamic recrystallization (PI-CDRX). According to the evolution of twinning under various deformation conditions, the effect of deformation temperature and strain rate on the evolution of twinning was characterized by the occurrence of DRX behavior.

Key words: GH4720Li alloy hot compression test dynamic softening mechanism particle-induced CDRX twinning boundary

Received: 04 May 2018

ZTFLH:	TG146.1
	TG146.1

	Service

	E-mail this article
	Add to citation manager
	E-mail Alert
	RSS
	（）
	Articles by authors
	Zhipeng WAN
	Tao WANG
	Yu SUN
	Lianxi HU
	Zhao LI
	Peihuan LI
	Yong ZHANG

URL:

https://www.ams.org.cn/EN/10.11900/0412.1961.2018.00179 OR https://www.ams.org.cn/EN/Y2019/V55/I2/213

Fig.1 OM (a) and SEM (b) images of initial microstructures of as-forged GH4720Li alloy

Fig.2 Curves of softening stress-temperature of the GH4720Li alloy under various strain rates

Fig.3 SEM images of the GH4720Li alloy deformed at 10 s^-1 and a strain of 0.8 with temperatures of 1060 ℃ (a), 1080 ℃ (b), 1100 ℃ (c) and 1120 ℃ (d)

Fig.4 OM images of the GH4720Li alloy deformed at 1 s^-1 and a strain of 0.8 with temperatures of 1060 ℃ (a), 1080 ℃ (b), 1100 ℃ (c) and 1120 ℃ (d)

Fig.5 OM images of the GH4720Li alloy deformed at 1100 ℃ and a strain of 0.8 with strain rates of 0.001 s^-1 (a), 0.01 s^-1 (b), 0.1 s^-1 (c) and 10 s^-1 (d)

Fig.6 TEM images of the GH4720Li alloy deformed at 1060 ℃ and a strain of 0.35 with strain rate of 0.1 s^-1 (a) and 1080 ℃ and a strain of 0.8 with strain rate of 0.001 s^-1 (b)

Fig.7 EBSD images of the GH4720Li alloy deformed at 1060 ℃, 1 s^-1 and strains of 0.35 (a) and 0.8 (b) (>15°, 5°~15° and 2°~5° boundaries are indicated by thick-black, thin-green and thin-orange lines, respectively. Σ3, Σ9 and Σ27 twins are displayed by thick red, thick blue and thick yellow lines, respectively. DDRX—discontinuous dynamic recrystallization)

Fig.8 Misorientations measured along the lines A1 (a) and A2 (b) marked in Fig.7a

Fig.9 EBSD images of the GH4720Li alloy deformed at 1100 ℃ and a strain of 0.8 with strain rates of 0.001 s^-1 (a), 0.1 s^-1 (b), 1 s^-1 (c) and 10 s^-1 (d) (>15°, 5°~15° and 2°~5° boundaries are indicated by thick-black, thin-green and thin-orange lines, respectively. Σ3, Σ9 and Σ27 twins are displayed by thick red, thick blue and thick yellow lines, respectively. GOS—grain orientation spread, HGBs—high angle grain boundaries)

Fig.10 EBSD images of the GH4720Li alloy deformed at strain rate of 0.1 s^-1 and a strain of 0.8 at temperatures of 1060 ℃ (a), 1080 ℃ (b) and 1120 ℃ (c) (>15°, 5°~15° and 2°~5° boundaries are indicated by thick-black, thin-green and thin-orange lines, respectively. Σ3, Σ9 and Σ27 twins are displayed by thick red, thick blue and thick yellow lines, respectively. α—the angle between ’grain boundary’ and ’tangent to the γ’ phase’)

Fig.11 Schematics of softening mechanisms evolution under different deformation conditions (PI-CDRX—particle-induced continuous dynamic recrystallization, COBM—continuous original boundary migration, ε—strain)

Fig.12 Effect of strain rate

(ε ˙)

and temperature on the formation of twinning boundaries of the GH4720Li alloy

[1]	Furrer D U, Fecht H J.γ′ formation in superalloy U720Li[J]. Scr. Mater., 1999, 40: 1215
[2]	Radis R, Schaffer M, Albu M, et al.Multimodal size distributions of γ′ precipitates during continuous cooling of Udimet 720 Li[J]. Acta Mater., 2009, 57: 5739
[3]	Chen J Y, Dong J X, Zhang M C, et al.Deformation mechanisms in a fine-grained Udimet 720Li nickel-base superalloy with high volume fractions of γ′ phases[J]. Mater. Sci. Eng., 2016, A673: 122
[4]	Liu F F, Chen J Y, Dong J X, et al.The hot deformation behaviors of coarse, fine and mixed grain for Udimet 720Li superalloy[J]. Mater. Sci. Eng., 2016, A651: 102
[5]	Sakai T, Belyakov A, Kaibyshev R, et al.Dynamic and post-dynamic recrystallization under hot, cold and severe plastic deformation conditions[J]. Prog. Mater. Sci., 2014, 60: 130
[6]	Zhou G W, Li Z H, Li D Y, et al.A polycrystal plasticity based discontinuous dynamic recrystallization simulation method and its application to copper[J]. Int. J. Plast., 2017, 91: 48
[7]	He G A, Tan L M, Liu F, et al.Unraveling the formation mechanism of abnormally large grains in an advanced polycrystalline nickel base superalloy[J]. J. Alloys Compd., 2017, 718: 405
[8]	Zhang L, Wang Q D, Liu G P, et al.Effect of SiC particles and the particulate size on the hot deformation and processing map of AZ91 magnesium matrix composites[J]. Mater. Sci. Eng., 2017, A707: 315
[9]	Huang K, Marthinsen K, Zhao Q L, et al.The double-edge effect of second-phase particles on the recrystallization behaviour and associated mechanical properties of metallic materials[J]. Prog. Mater. Sci., 2018, 92: 284
[10]	Li F L, Fu R, Yin F J, et al.Impact of γ′(Ni3(Al, Ti)) phase on dynamic recrystallization of a Ni-based disk superalloy during isothermal compression[J]. J. Alloys Compd., 2017, 693: 1076
[11]	Yu Q Y, Yao Z H, Dong J X.Deformation and recrystallization behavior of a coarse-grain, nickel-base superalloy Udimet 720Li ingot material[J]. Mater. Charact., 2015, 107: 398
[12]	Wan Z P, Sun Y, Hu L X, et al.Experimental study and numerical simulation of dynamic recrystallization behavior of TiAl-based alloy[J]. Mater. Des., 2017, 122: 11
[13]	Yuan X Y, Chen L Q.Hot deformation at elevated temperature and recrystallization behavior of a high manganese austenitic TWIP steel[J]. Acta Metall. Sin., 2015, 51: 651(袁晓云, 陈礼清. 一种高锰奥氏体TWIP钢的高温热变形与再结晶行为[J]. 金属学报, 2015, 51: 651)
[14]	Li Q, Guo H Z, Wang Y W, et al.Hot deformation behaviors and microstructure evolution of GH4049 alloy[J]. J. Mater. Eng., 2014, (12): 55(李卿, 郭鸿镇, 王彦伟等. GH4049合金的热变形行为及组织演变[J]. 材料工程, 2014, (12): 55)
[15]	Yang Z Q, Liu Z D, He X K, et al.Hot deformation behavior of SA508Gr.4N steel for reactor pressure vessels[J]. J. Mater. Eng., 2017, 45(8): 88(杨志强, 刘正东, 何西扣等. 反应堆压力容器用SA508Gr.4N钢的热变形行为[J]. 材料工程, 2017, 45(8): 88)
[16]	Monajati H, Jahazi M, Bahrami R, et al.The influence of heat treatment conditions on γ′ characteristics in Udimet? 720[J]. Mater. Sci. Eng., 2004, A373: 286
[17]	Hallberg H, Svendsen B, Kayser T, et al.Microstructure evolution during dynamic discontinuous recrystallization in particle-containing Cu[J]. Comput. Mater. Sci., 2014, 84: 327
[18]	Han Y, Yan S, Yin B G, et al.Effects of temperature and strain rate on the dynamic recrystallization of a medium-high-carbon high-silicon bainitic steel during hot deformation[J]. Vacuum, 2018, 148: 78
[19]	Ahmed K, Tonks M, Zhang Y F, et al.Particle-grain boundary interactions: A phase field study[J]. Comput. Mater. Sci., 2017, 134: 25
[20]	Langelier B, Persaud S Y, Korinek A, et al.Effects of boundary migration and pinning particles on intergranular oxidation revealed by 2D and 3D analytical electron microscopy[J]. Acta Mater., 2017, 131: 280
[21]	Mousavizade S M, Pouranvari M, Ghaini F M, et al.Dynamic recrystallization phenomena during laser-assisted friction stir processing of a precipitation hardened nickel base superalloy[J]. J. Alloys Compd., 2016, 685: 806
[22]	Doherty R D, Hughes D A, Humphreys F J, et al.Current issues in recrystallization: A review[J]. Mater. Sci. Eng., 1997, A238: 219
[23]	Zhilyaev A P, Langdon T G.Using high-pressure torsion for metal processing: Fundamentals and applications[J]. Prog. Mater. Sci., 2008, 53: 893
[24]	Rout M, Ranjan R, Pal S K, et al.EBSD study of microstructure evolution during axisymmetric hot compression of 304LN stainless steel[J]. Mater. Sci. Eng., 2018, A711: 378
[25]	Son K T, Kim M H, Kim S W, et al.Evaluation of hot deformation characteristics in modified AA5052 using processing map and activation energy map under deformation heating[J]. J. Alloys Compd., 2018, 740: 96
[26]	Yin X Q, Park C H, Li Y F, et al.Mechanism of continuous dynamic recrystallization in a 50Ti-47Ni-3Fe shape memory alloy during hot compressive deformation[J]. J. Alloys Compd., 2017, 693: 426
[27]	Kapoor R, Reddy G B, Sarkar A.Discontinuous dynamic recrystallization in α-Zr[J]. Mater. Sci. Eng., 2018, A718: 104
[28]	Hadadzadeh A, Mokdad F, Wells M A, et al.A new grain orientation spread approach to analyze the dynamic recrystallization behavior of a cast-homogenized Mg-Zn-Zr alloy using electron backscattered diffraction[J]. Mater. Sci. Eng., 2018, A709: 285
[29]	Pradhan S K, Mandal S, Athreya C N, et al.Influence of processing parameters on dynamic recrystallization and the associated annealing twin boundary evolution in a nickel base superalloy[J]. Mater. Sci. Eng., 2017, A700: 49
[30]	Azarbarmas M, Aghaie-Khafri M, Cabrera J M, et al.Dynamic recrystallization mechanisms and twining evolution during hot deformation of Inconel 718[J]. Mater. Sci. Eng., 2016, A678: 137
[31]	Li Z G, Zhang L T, Sun N R, et al.Effects of prior deformation and annealing process on microstructure and annealing twin density in a nickel based alloy[J]. Mater. Charact., 2014, 95: 299
[32]	Zhang H B, Zhang K F, Zhou H P, et al.Effect of strain rate on microstructure evolution of a nickel-based superalloy during hot deformation[J]. Mater. Des., 2015, 80: 51
[33]	Aghaie-Khafri M, Mahmudi R.Optimizing homogenization parameters for better stretch formability in an Al-Mn-Mg alloy sheet[J]. Mater. Sci. Eng., 2005, A399: 173

[1]	LIU Chao, YAO Zhihao, JIANG He, DONG Jianxin. The Feasibility and Process Control of Uniform Equiaxed Grains by Hot Deformation in GH4720Li Alloy with Millimeter-Level Coarse Grains[J]. 金属学报, 2021, 57(10): 1309-1319.
[2]	WANG Tao,WAN Zhipeng,LI Zhao,LI Peihuan,LI Xinxu,WEI Kang,ZHANG Yong. Effect of Heat Treatment Parameters on Microstructure and Hot Workability of As-Cast Fine Grain Ingot of GH4720Li Alloy[J]. 金属学报, 2020, 56(2): 182-192.
[3]	Tao WANG, Zhipeng WAN, Yu SUN, Zhao LI, Yong ZHANG, Lianxi HU. Dynamic Softening Behavior and Microstructure Evolution of Nickel Base Superalloy[J]. 金属学报, 2018, 54(1): 83-92.
[4]	JIA Bin PENG Yan. CONSTITUTIVE RELATIONSHIPS OF Nb MICROALLOYED STEEL DURING HIGH TEMPERATURE DEFORMATION[J]. 金属学报, 2011, 47(4): 507-512.

No Suggested Reading articles found!

Viewed

Full text

Abstract

Cited

Shared

Discussed