The Effects of Hot-Pack Coating Materials on the Pack Rolling Process and Microstructural Characteristics during Ti-46Al-8Nb Sheet Fabrication.

Published on Feb 7, 2020in Materials3.057
· DOI :10.3390/MA13030762
Haohong Huang1
Estimated H-index: 1
(NU: Northeastern University),
Minle Liao1
Estimated H-index: 1
(NU: Northeastern University)
+ 2 AuthorsZhaodong Wang18
Estimated H-index: 18
(NU: Northeastern University)
Sources
Abstract
The effects of the package materials on the hot workability and stress-strain characteristics of high-Nb TiAl alloy with a nominal composition of Ti-46Al-8Nb (in at.%) were systematically studied via “sandwich structure” hot compression. TiAl sheet fabrication was conducted by hot pack rolling, and the microstructural characteristics and deformation mechanisms were investigated. Based on the analysis of compressed samples and stress-strain curves, the stainless steel/TiAl structure showed better deformation compatibility with homogeneous deformation and decreasing resistance. However, severe interfacial reactions were inevitable. Meanwhile, for the titanium alloy/TiAl structure, few interfacial reactions happened, but wavy deformation and high resistance complicated the compression process. Finally, a package structure with an outer stainless steel isolation layer and inner titanium alloy was determined for the pack rolling process. A TiAl sheet with no crack defects was obtained with 80% reduction. The pack-rolled TiAl sheet took on alternate microstructure of the grain-boundary Al-enriched ribbons and elongated lamellar colonies ribbons. The grain-boundary recrystallized α2 phase, lumpy γ phase, and massive α2/γ lamellae could be observed, which led to the scatter microstructure. The microstructural characteristics mainly resulted from the solute segregations of as-cast Ti-46Al-8Nb alloys, which triggered the local flow softening and deformation incompatibility during hot pack rolling.
📖 Papers frequently viewed together
6 Authors (Zhengzhang Shen, ..., Zi Kui Liu)
32 Citations
6 Authors (刘仁慈, ..., 杨锐)
2 Citations
References28
Newest
#1Tianrui Li (NU: Northeastern University)H-Index: 4
#2Guohuai Liu (NU: Northeastern University)H-Index: 8
Last. Raja Devesh Kumar Misra (UTEP: University of Texas at El Paso)H-Index: 67
view all 7 authors...
To elucidate the hot deformation characteristics of TiAl alloys, flow stress prediction, microstructural evolution and deformation mechanisms were investigated in Ti-44Al-5Nb-1Mo-2V-0.2B alloy by isothermal compression tests. A constitutive relationship using the Arrhenius model involving strain compensation and back propagation artificial neural network (BP-ANN) model were developed. A comparison of two models suggested that the BP-ANN model had excellent capabilities and was more accurate in p...
8 CitationsSource
#1Tianrui Li (NU: Northeastern University)H-Index: 4
#2Guohuai Liu (NU: Northeastern University)H-Index: 8
Last. Zhaodong Wang (NU: Northeastern University)H-Index: 18
view all 7 authors...
Hot deformation behavior, microstructural evolution and flow softening mechanism were investigated in Ti–46Al–8Nb alloy via isothermal compression approach. The true stress–strain curves exhibited typical work hardening and flow softening, in which the dependence of the peak stress on temperature and strain rate was obtained by hyperbolic sine equation with Zener–Hollomon (Z) parameter, and the activation energy was calculated to be 446.9 kJ/mol. The microstructural analysis shows that the alter...
9 CitationsSource
#1Mingao Li (HIT: Harbin Institute of Technology)H-Index: 7
#2Shulong Xiao (HIT: Harbin Institute of Technology)H-Index: 20
Last. Baoyou Zhang (HIT: Harbin Institute of Technology)H-Index: 1
view all 6 authors...
Abstract The high-temperature properties, microstructure evolution and deformation behavior of a novel Ti-43Al-6Nb-1Mo-1Cr(at.%) alloy were studied in this paper. The ultimate tensile strength (UTS) and elongation (δ) were tested at 800, 850, and 900 °C, in which the excellent strength 551 MPa, 510 MPa, and 382 MPa, and elongation 2.9%, 12.7%, and 16.8% were exhibited, respectively. Isothermal compression tests were carried out in the temperature range of 1100–1250 °C and strain rate range of 0....
13 CitationsSource
#1Yang (CAS: Chinese Academy of Sciences)H-Index: 1
The history of research and development of g-Ti Al intermetallic alloys was outlined and divided into 4 stages: starting(1974~1985), revolutionary(1986~1995), emerging(1996~2005) and specialty materials(2006~). Major events and landmarks at the different stages were recounted to provide a framework for understanding scientific and technological progress. Key advances in the following 6 areas were reviewed: alloying, microstructure type, primary processing(melting), secondary processing(hot worki...
45 CitationsSource
#1R. K. GuptaH-Index: 1
#2P. RamkumarH-Index: 1
Gamma phase based two phase (+2) titanium aluminides have promising potential as high temperature structural materials particularly for aerospace systems due to light weight. They are potential candidate materials for metallic thermal protection system (MTPS) of reentry vehicles. Limitations with respect to processing have been reported due to poor formability below 700 0 C. However, different specialized techniques have been evolved to realize the material in various forms. The present paper ...
2 Citations
#1Xiaopeng Liang (CSU: Central South University)H-Index: 18
#2Yong Liu (CSU: Central South University)H-Index: 42
Last. Yuehui He (CSU: Central South University)H-Index: 33
view all 6 authors...
Abstract The microstructural and mechanical properties of powder metallurgical (PM) Ti–47Al–2Cr–0.2Mo alloy plates under various hot pack-rolling conditions were investigated. The PM TiAl plates show recrystallized and duplex microstructure. The dynamic recrystallization mainly occurred in β phase at the beginning of deformation, and a large amount of dislocations and sub-grains formed in γ phase. The dynamic recrystallization of γ phase is the main mechanism for the flow softening in the later ...
31 CitationsSource
#1Guohuai Liu (HIT: Harbin Institute of Technology)H-Index: 1
#2Xinzhong Li (HIT: Harbin Institute of Technology)H-Index: 18
Last. Hengzhi Fu (HIT: Harbin Institute of Technology)H-Index: 35
view all 6 authors...
Abstract Bridgman type directional solidification experiments were conducted for Ti–46Al–8Nb alloy in a wide range of growth rates (1–70 μm/s). The microstructure, microsegregation and the formation of B2 phase were investigated. Nearly planar and shallow cellular growths of primary β phase were observed at the growth rates of 1 and 2 μm/s respectively, and a fully α 2 / γ lamellar structure was formed finally. The growth rates of (2–5 μm/s) and (⩾5 μm/s) resulted in the transient cellular-dendr...
36 CitationsSource
#1Kunal Kothari (UMD: University of Maryland, College Park)H-Index: 4
#2Ramachandran Radhakrishnan (UMD: University of Maryland, College Park)H-Index: 6
Last. Norman M. Wereley (UMD: University of Maryland, College Park)H-Index: 64
view all 3 authors...
Abstract Gamma titanium aluminides display attractive properties for high temperature applications. For over a decade in the 1990s, the attractive properties of titanium aluminides were outweighed by difficulties encountered in processing and machining at room temperature. But advances in manufacturing technologies, deeper understanding of titanium aluminides microstructure, deformation mechanisms, and advances in micro-alloying, has led to the production of gamma titanium aluminide sheets. An i...
271 CitationsSource
#1David W. A. Rees (Brunel University London)H-Index: 16
Abstract The theory of plane strain compression is applied to rolled aluminium alloy sheet. Two contrasting grades of the alloy are tested: naturally aged AC 120 and half-hard HE 30. While AC 120 displays a smooth stress–strain curve under homogenous straining, HE30 shows a serrated stress–strain curve due to its banded plastic strain behaviour. It is shown that, provided the r -values can be established reliably to characterise each sheet’s orthotropy, a flow curve to large strain (≃2) is provi...
15 CitationsSource
#1Guo-huai Liu (HIT: Harbin Institute of Technology)H-Index: 1
#2Xin-zhong Li (HIT: Harbin Institute of Technology)H-Index: 5
Last. Fu Hengzhi (HIT: Harbin Institute of Technology)H-Index: 13
view all 6 authors...
Abstract Directional solidification experiments were conducted for Ti-46Al-8Nb alloy at the growth rates ranging from 3 to 70 μm/s. The microstructure evolution and microsegregation pattern were investigated. In the range of growth rate, a regular dendritic structure appears and the primary dendrite spacing decreases with increasing growth rate. The peritectic reaction is observed during the solidification and the final microstructure is composed of α 2 /γ lamellar structure and retained β( B 2)...
11 CitationsSource
Cited By1
Newest
#1Hamid Reza Javadinejad (HBNU: Hanbat National University)H-Index: 1
#2Giseung Shin (HBNU: Hanbat National University)H-Index: 1
Last. Jeoung Han Kim (HBNU: Hanbat National University)H-Index: 23
view all 7 authors...
Abstract Pack rolling is an effective process for manufacturing Ti-6Al-4V products, especially thin sheets; however, it tends to cause surface defects. Surface ridging is the most significant surface defect produced during the pack rolling of thin sheets. Hence, in this study, the effects of pack-rolling conditions on the origin of surface ridging on Ti–6Al–4V alloy surfaces were investigated using experimental and numerical techniques. Pack rolling was carried out at temperatures of 830, 860, 9...
Source