Effect of temperature and time, the interlayer on microstructure and mechanical properties of Transient Liquid Phase (TLP) bonding of AISI321 stainless steel

Subject Areas : journal of New Materials

M.A Misaghi ¹ , رضا Bakhtiari ²

1 - دانشجوی کارشناسی ارشد مهندسی مواد، دانشکده فنی و مهندسی، دانشگاه آزادواحد علوم وتحقیقات کرمانشاه، کرمانشاه، ایران
2 - استادیار، دکترای مهندسی مواد، گروه مهندسی مواد، دانشگاه رازی کرمانشاه، کرمانشاه، ایران

Received: 2014-12-17 Accepted : 2017-11-16 Published : 2017-08-23

Keywords: mechanical properties, TLP bonding, AISI 321 steel, MBF-30 and MBF-20 interlayers,

Abstract :

According to the industry’s need to an appropriate bonding process for components made of AISI 321 austenitic stainless steel, which is used in power-plant parts such as turbines, transient liquid phase (TLP) bonding of AISI 321 steel using  MBF-30 and MBF-20  interlayers was studied in this research. TLP bonding was performed in a vacuum furnace at 1050, 1100 and 1150 ^oC  for 30-120 minutes. The microstructural studies were conducted on the joints using an optical microscope and an scanning electron microscope (SEM). Phase analysis of the joints was also performed a SEM/EDS and XRD system. To investigate the distribution of elements across the joints, line scan analysis was used. The shear strength test and the microhardness  measurement test were conducted on the joints, in order to study the joints’ mechanical properties. The minimum time or complete isothermal solidification at 1050, 1100 and 1150^oC was obtained as 75, 45 and 30 minutes, respectively. At the incomplete isothermal solidification condition, Fe-B, Cr-B,    Ni-Si and Ni-B phases were observed at the joint centerline and diffusion affected zone (DAZ). With increasing bonding temperature and time, more homogenous joint, lower hardness at the different zones of the joints and higher shear strength were obtained. The maximum shear strength for MBF-30 interlayer was obtained as 99 and 98 percent of that of the base metal, and for MBF-20 interlayer was obtained as 95 and 94 percent of that of the base metal, respectively.

References:

1- M. Mazar Atabaki, "Partial transient liquid phase diffusion bonding of Zircaloy-4to stabilized austenitic stainless steel 321 using active titanium filler metal", J.Manuf Sci Eng;133(5):99–110,2011.
2-M. Mazar Atabaki, M.E. Bajgholi, E.H. Dehkordi "Partial transient liquid phase diffusion bonding of zirconium alloy (Zr–2.5Nb)to stainless steel 321",Materials and Design 42,172–183,2012.      

3- M.A.Arafin , M. Medraj , D.P. Turner , P. Bocher "Effect of alloying elements on the isothermal solidification during TLP bonding of SS 410 and SS 321 using a BNi-2 interlayer" Materials Chemistry and Physics 106 , 109–11,2007.         

4- E.A. Brandes , G.B. Brook , "Smithells metal reference book" 7th edu,11-7-11-485,Oxford,Uk,Butterworth,Heinemann, 1992.

5- P. Villars, A Prince and H. Okamoto: "Handbook of Ternary Alloy Phase Diagrams", ASM International, Materials Park, OH, USA, 5508-5513,1995.

6-  J.S.C. Jang and H.P. Shih: "Evolution of Microstructure of AlSI 304 Stainless Steel Joint Brazed by Mechanically Alloyed Nickel Base Filler with Different Silicon Content", Journal of Material Science Letters, Vol. 22, 79-82, 2003.
  7- R. Bakhtiari, A. Ekrami. "The effect of gap size on the microstructure and mechanical properties of the tranient liquid phase bonded FSX-414 superalloy". Mat 40,130-137,2012.   

8- M.Pouranvari, A.Ekrami, AH.Kokabi "Microstructure–properties relationship of TLP-bonded GTD-111 nickel-base superalloy". Mater Sci Eng A;490:229–34,2008.

9- W.F. Gale and E.R. Wallach: "Wettability of nickel alloys by boron containing brazes", Welding Research, 76s-79s,1991.

10-  O.A. Idowu, N.L. Richards, M.C. Chaturvedi, Mater. Sci. Eng. A 397, 98–112,2005.

11-R.Bakhtiari, A.Ekrami, Khan,TI. "The  effect  of  TLP  bonding  temperature  on   microstructural  and  mechanical property  of  joints  made  using  FSX-414  superalloy",Mat A546, 291-300,2012.

12- R. Bakhtiari," The  effect  of  TLP  bonding  temperature  on  microstructural  and  mechanical property  of  joints  made  using  FSX-414  superalloy" . Ph.D Thesis on Materials Engineering . Sharif University .( In Persian),2012.

13- م.رحمانی، م.شمعانیان، م.کسیری" بررسی ریز ساختار و خواص مکانیکی جوشهای نامشابه فولاد زنگ نزن سوپر دو فازی UNS32750 به فولاد زنگ نزن آستنیتی AISI304L "مجله مواد نوین مرودشت، جلد 3، شماره 2، زمستان 1391.