INVESTIGATION OF BONDING PHASE DIMENSION ON SHEAR STRENGTH OF SUPERALLOY BRAZED BY ACTVE FILLER MATERIAL

Authors : Mudhafar MOHAMMED, Saba Khathim

Pages : 52-58

View : 20 | Download : 13

Publication Date : 2020-07-17

Article Type : Conference Paper

Abstract :In  this  study, Nickel  based  superalloy  In 738 LC was  brazed  by using  insert ignore into journalissuearticles values(Ni-Ti);  and insert ignore into journalissuearticles values( Ni-Ti-Al);  alloys which  are  an active  filler  alloys  under protective atmosphere insert ignore into journalissuearticles values( using a  high purity  99.999  Argon gas );.  Five brazing temperatures insert ignore into journalissuearticles values(1135, 1025, 985, 825, 725 ºC); were chosen based on the solidus temperatures of   insert ignore into journalissuearticles values(Ni-Ti); and   insert ignore into journalissuearticles values(Ni-Al); filler alloys in order to investigate the effects of these temperatures on the performance of the brazed joints. Brazing processes were carried out over a period of   time insert ignore into journalissuearticles values(15min);  to ensure  that  the filler  alloys were  melted  completely. The performance of   brazing process was evaluated in terms of bonding strength by shear test.  The results  revealed that  a maximum value  of shear  strength  insert ignore into journalissuearticles values( 29MPa );  was  obtained  at  brazing temperature insert ignore into journalissuearticles values( 985ºC ); as compared  with other temperatures.   It  was  observed that  the  highest shear strength was  influenced  by  the formation  of  insert ignore into journalissuearticles values( Ni3Ti ); phase.    Micro - hardness  testing  appears  a gradual  increasing  in hardness  towards the  centerline of  the  joint  indicating  that  the  composition of  bonded  layer consists  of  a hard  intermetallic  phases  of   varying  composition  at different depth.  The  samples  bonded   by  insert ignore into journalissuearticles values( 5% Ni 5%Ti 90%Al );  at   825ºC   revealed the  higher  value  insert ignore into journalissuearticles values( 841.7 );  HV  due  to   intermetallic  and  centerline  eutectic constituents  in the center of  brazing seam.
Keywords : Brazing, Active filler alloy, Brazing temperatures, Nickel based superalloy, Shear strength