Influence of Hot-working and Solution Annealing on Microstructure and Mechanical Properties of Haynes 188

Document Type : Original Articles

Authors

• Mahdi Samie zafarghandi
• S.Mehdi Abbasi
• Maryam Morakabati

Malek-e ashtar university of technology

10.22067/ma.v31i1.65787

Abstract

In present work effects of strain in hot working process and solution annealing, on microstructure and subsequent mechanical properties were investigated. The billet were hot rolled into final reduction in thickness 60 and 85% (R-60 and R-85) at 1150 ˚C. After that, solution annealing at 1140 ˚C to 1200 ˚C for 10 to 120 minutes were conducted to optimize of mechanical properties. The microstructures revealed grain size of R-85 sample was lower than another, but grain growth was observed for annealed sample above 1140 ˚C after 30 minutes. EDS analysis shown M6C carbide rich of tungsten is only precipitated carbide. It's also found that grain growth rate is much more for R-85 sample. SEM evaluations also confirmed faster solution rate of carbides for R-85 sample. Yield strength of R-85 is very higher relative to R-60 while after annealing at 1140 ˚C for 10 minutes it decreased drastically. Annealing in same condition for R-60 sample cause not only decreasing of strength, even improved ductility.

Keywords

• Superalloy
• Strain
• solution annealing
• Mechanical properties
• microstructure evaluation

---

References

1. B. Geddes, H. Leon, and X. Huang, Superalloys: alloying and performance. ASM International, (2010).

2. M. J. Donachie and S. J. Donachie, Superalloys: a technical guide. ASM international, (2002).

3. J. R. Davis, "ASM specialty handbook: Nickel, Cobalt, and their alloys," ASM International, Member/Customer Service Center, (2000).

4. H. Chandler, Heat treater's guide: practices and procedures for nonferrous alloys. ASM international, (1996).

5. M. Mori, K. Yamanaka, S. Sato, K. Wagatsuma, and A. Chiba, "Microstructures and mechanical properties of biomedical Co-29Cr-6Mo-0.14 N alloys processed by hot rolling," Metallurgical and Materials Transactions A, vol. 43, no. 9, pp. 3108-3119, (2012).

6. K. Yamanaka, M. Mori, and A. Chiba, "Enhanced mechanical properties of as-forged Co-Cr-Mo-N alloys with ultrafine-grained structures," Metallurgical and Materials Transactions A, vol. 43, no. 13, pp. 5243-5257, (2012).

7. R. Gupta, M. Karthikeyan, D. Bhalia, B. Ghosh, and P. Sinha, "Effect of microstructure on mechanical properties of refractory Co-Cr-W-Ni alloy," Metal Science and Heat Treatment, vol. 50, no. 3-4, pp. 175-179, (2008).

8. J. Favre, "Recrystallization of L-605 cobalt superalloy during hot-working process," Thesis submited

for degree of Doctor of philosophy, Citeseer, (2013).

9. Standard, "E92, Standard test method for vickers hardness of metallic materials, vol. 2," West Conshohocken, PA: ASTM International, (2003).

10. Standard, "E8 test methods of tension testing of metallic materials" ASTM International, [metric], 2003.

11. W. Gui, H. Zhang, M. Yang, T. Jin, X. Sun, and Q. Zheng, "The investigation of carbides evolution in a cobalt-base superalloy at elevated temperature", Journal of Alloys and Compounds, vol. 695, pp. 1271-1278, (2017).

12. K. Yamanaka, M. Mori, and A. Chiba, "Influence of carbon addition on mechanical properties and microstructures of Ni-free Co–Cr–W alloys subjected to thermomechanical processing", Journal of the mechanical behavior of biomedical materials, vol. 37, pp. 274-285, (2014).

13. K. Yamanaka, M. Mori, and A. Chiba, "Developing high strength and ductility in biomedical Co–Cr cast alloys by simultaneous doping with nitrogen and carbon," Acta biomaterialia, vol. 31, pp. 435-447, (2016).

14. S.-H. Lee, E. Takahashi, N. Nomura, and A. Chiba, "Effect of carbon addition on microstructure and mechanical properties of a wrought Co-Cr-Mo implant alloy," Materials transactions, vol. 47, no. 2, pp. 287-290, (2006).

15. J. Favre, D. Fabrègue, E. Maire, and A. Chiba, "Grain growth and static recrystallization kinetics in Co–20Cr–15W–10Ni (L-605) cobalt-base superalloy," Philosophical Magazine, vol. 94, no. 18, pp. 1992-2008, (2014).

16. K. Ueki, K. Ueda, and T. Narushima, "Microstructure and Mechanical Properties of Heat-Treated Co-20Cr-15W-10Ni Alloy for Biomedical Application," Metallurgical and Materials Transactions A, vol. 47, no. 6, pp. 2773-2782, (2016).

17. B. Lin, "Investigating annealing twin formation mechanisms in face-centered cubic Nickel," Thesis

submited for degree of Doctor of philosophy, Carnegie Mellon University, (2015).

18. D. A. Porter, K. E. Easterling, and M. Sherif, Phase Transformations in Metals and Alloys, (Revised Reprint). CRC press, (2009).