اثر بور و زیرکونیوم بر ریزساختار و استحکام خستگی سوپر آلیاژ Nimonic 105 در دمای ˚C 750

نوع مقاله: مقاله پژوهشی

نویسندگان

دانشگاه صنعتی مالک اشتر

چکیده

در این تحقیق، ریزساختار و خواص خستگی کم‌چرخه دما بالای سوپر آلیاژ Nimonic 105 در حضور بور و زیرکونیم مورد بررسی قرار گرفته است. آزمون خستگی کم چرخه در شرایط کرنش کنترل (کرنش 8/0) با نرخ بارگذاری s-13-10×3 در 0=R در دمای °C 750 در اتمسفر محیط انجام شده است. نتایج نشان داد که عنصر زیرکونیم سبب تشکیل کاربیدهای ZrC در مرز دانه‌ها و درون دانه‌ها می‌گردد. همچنین افزودن عنصر زیرکونیم سبب کاهش اندازه دانه آلیاژ شده است. در غیاب عنصر زیرکونیم رسوبات کاربیدی عمدتاً از نوع (Cr,Mo)23C6 و در مرزدانه‌ها یافت می‌شوند. عنصر بور سبب کاهش اندازه رسوبات ´γ می‌شود. با افزودن بور دوقلویی‌ها در ساختار افزایش چشمگیری دارد. افزودن عنصر بور تا 013/0% وزنی سبب بهبود خواص خستگی کم چرخه دما بالای آلیاژ می‌شود. در حضور( 013/0% وزنی) بور، شکست از نوع درون دانه‌ای و بین دانه‌ای است؛ در حالی که با افزودن عنصر زیرکونیم تا 16/0% وزنی نوع شکست کاملاً بین دانه‌ای می‌باشد. تشکیل کاربیدهای سخت صفحه‌ای MC ناشی از افزودن Zr که یک شبکه غیر‌کوهرنت با زمینه و مرزدانه‌ها دارند، مکان‌های شروع و تکثیر ریزترک‌ها را فراهم می‌کند. در نتیجه در حضور عنصر زیرکونیم ترک‌های ثانویه افزایش و عمر خستگی آلیاژ کاهش می‌یابد.

کلیدواژه‌ها


عنوان مقاله [English]

Effects of B and Zr on the microstructure and low cycle fatigue properties of Nimonic 105 superalloy at 750 C

نویسنده [English]

  • masumeh seifollahi
چکیده [English]

Microstructure and low cycle-high temperature fatigue properties of Nimonic 105 superalloys with and without B and Zr is investigated in this article. Fully reversed strain-controlled tests were performed at 750°C, R=0 and strain rate of 3×10-3 s-1. The results show that Zr cause to ZrC formation at the grain boundaries and grain interior. Also Zr is reduced the grain size of the alloys. The carbides at the absence of Zr is of the type of (Cr,Mo)23C6 at the grain boundaries. The ᵧ’ size decreased by B additions to the alloys and the number of twins increased. 0.013wt% B improves low cycle-high temperature fatigue of the alloy. At the presence of B, fracture is of the types of intragranular and intergranular but by addition of 0.16wt% Zr the only fracture type is intragranular. Hard and none coherent MC type precipitates by Zr addition are the initiation place for micrcraking and the cause of fatigue life reduction .

کلیدواژه‌ها [English]

  • Nimonic 105 superalloy
  • Low Cycle-High temperature fatigue (LCF)
  • Boron
  • zirconium
1. Y. Xu and C. Yang, "Strengthening behavior of Al and Ti elements at room temperature and high temperature in modified Nimonic 80A", Materials Chemistry and Physics, 134, 2012, 706-715.

2. M. Dusic, "Void formation in Nimonic 105 superalloyat high temperature and stress", Materials Science and Technology,2, 1986, 559-563.

3. V. Seetharaman and K. Bhanu, "Precipitation and Tensile Deformation Behaviour of a Nimonic 105 Superalloy", ActaMetallurgica, 35, 1987, 565-575.

4. K. K. Sharma, D. Banerjee and S. N. Tewari, "Effect of Reverse-aging Treatment on the Microstructure and Mechanical Properties of Nimonic Alloys", Materials Science and Engineering A, 104, 1988, 131-140.

5- R. Viswanathan, " Damage Mechanisms and Life Assessment of High Temperature Components", ASM International, 1989.

6. E. Andrieu, G. Hochstetter, R. Molins and A. Pineau,"Intergranular Crack Tip Oxidation Mechanisms in Nickel-Based Superalloy",Materials Science and Engineering, 154,1992, 21–28.

 

7. H.Ghonem and D. Zheng, "Depth of intergranular oxygen diffusion during environment-dependent fatigue crack growth in alloy 718",Materials Science and Engineering, 150,1992, 151–160.

8. K. C. Antony, and J. F. Radavich, "Solute Effects of Boron and Zirconium on Microporosity", Superalloys, 1976, 137-146.

9. Z. Hu, H. Song, S. Guo, and W. Sun, "Role of P, S and B on Creep Behavior of Alloy 718", Materials Science & Technology, 17, 2001, 399-402.

10. H.E. Huang, and C.H. Koo, "Effect of Zirconium on Microstructure and Mechanical Properties of Cast Fine-Grain CM 247 LC Superalloy", Materials Transactions, 45, 2004, 554-561.

11. B.C. Yan and J. Zhang, "Effect of Boron Additions on the Microstructure and Transverse Properties of a Directionally Solidified Superalloy", Materials Science and Engineering A, 474, 2008, 39–47.

12. S. Floreen and J. M. Davidson, "The Effects of B and Zr on The Creep and Fatigue Crack Growth Behavior of a Ni-Base Superalloy", Metallurgical Transactions A, 14, 1983, 895-901.

13. J. Gayda and T.P.Gabb, "Fatigue Crack Propagation of Nickel-Base Superalloys at 650°C ", Low cycle fatigue , ASTM ST942, 1988, 293-309.

14.Xiao, L., D. L. Chen, and M. C. Chaturvedi, "Effect of boron and carbon on thermomechanical fatigue of IN 718 superalloy: Part I. Deformation behavior", Materials Science and Engineering A, 437, 2006, 157-171.

15.L. Xiao, M. C. Chaturvedi, and D. L. Chen, "Effect of boron on the low-cycle fatigue behavior and deformation structure of INCONEL 718 at 650° C", Metallurgical and Materials Transactions A, 35, 2004, 3477-3487.

16.L.Xiao, M. C. Chaturvedi, and D. L. Chen, "Low-cycle fatigue behavior of INCONEL 718 superalloy with different concentrations of boron at room temperature", Metallurgical and materials Transactions A, 36, 2005, 2671-2684.

17.L.Xiao, D. L. Chen, and M. C. Chaturvedi, "Effect of boron on fatigue crack growth behavior in superalloy IN 718 at RT and 650 C." Materials Science and Engineering A 428.1 (2006): 1-11.

18. L. Xiao, D. L. Chen, and M. C. Chaturvedi, "Effect of boron and carbon on thermomechanical fatigue of IN 718 superalloy: Part I. Deformation behavior", Materials Science and Engineering A, 437, 2006, 157-171.

19. V. Seetharaman, "Precipitation and tensile deformation behaviour of a nimonic 105 superalloy",ActaMetallurgica, 35, 1987, 565-575.

20. J. Zhang, , and R. F. Singer. "Effect of Zr and B on castability of Ni-based superalloy IN792", Metallurgical and materials Transactions A, 35, 2004, 1337-1342.

21.T. Fedorova, J. Rosler, B. Gehrmann and j. klower, " influence of B and Zr on microstructure and mechanical properties of alloy 718", superalloy 718 and derivatives, 2010, 837-846.

22. P.J. Zhou, J. J.Yu, X. F. Sun, H. R. Guan, and Z. Q. Hu, "The role of boron on a conventional nickel-based superalloy", Materials Science and Engineering A, 491, 2008,159-163.

23.C.Wang, Y.Guo, J.Guo andL.Zhou "Microstructural stability and mechanical properties of a boron modified Ni–Fe based superalloy for steam boiler applications", Materials Science and Engineering A, 639, 2015,380-388.

24.J. Dahal, K.Maciejewski, and H.Ghonem. "Loading frequency and microstructure interactions in intergranular fatigue crack growth in a disk Ni-based superalloy", International Journal of Fatigue, 57, 2013, 93-102.

25.L. Wang, S. Wang, X. Song, Y.Liu, andG.Xu, G. "Effects of precipitated phases on the crack propagation behaviour of a Ni-based superalloy" International Journal of Fatigue, 62, 2014, 210-216.

26.S. K. Hwang, H. N. Lee, and B. H. Yoon, "Mechanism of cyclic softening and fracture of an Ni-Base γ′-Strengthened alloy under low-Cycle fatigue", Metallurgical Transactions A 20, 1989, 2793-2801.

27.D. D. Krueger, D. A. Stephen, and H. V. Robert, "Effects of grain size and precipitate size on the fatigue crack growth behavior of alloy 718 at 427°C", Metallurgical transactions A, 18, 1987, 1431-1449.

28. H. Ghonem, and D. Zheng, "Depth of intergranular oxygen diffusion during environment-dependent fatigue crack growth in alloy 718", Materials Science and Engineering A, 150, 1995, 151-160.