THE EFFECT OF BORON AND CARBON ADDITION ON WELDABILITY OF DS TMS-75 SUPERALLOY
来源期刊：Acta Metallurgica Sinica2005年第1期
论文作者：M.C.Chaturvedi Y.L.WANG N.L.Richards
Key words：Ni-based superalloy; low melting point constituents; liquation cracking;
Abstract: Four alloys TMS-75 (Base), Base+B, Base+C and TMD-103 (Base+B+C) with varying levels of B, C were directionally solidified (DS), and their weldability was investigated by bead-onplate electron beam welding.It was found that cracking occurred in the weld-metal, as well as in the heat affected zone (HAZ).Both γ/γ' and/or γ/carbide eutectic contributed to the weld-metal cracking, and the γ/γ' eutectic was found to be mainly responsible for cracking in HAZ However, constitutional liquation of carbides seems to have made some contribution also.The B addition had a detrimental effect on HAZ cracking susceptibility, while C addition improved it appreciably even in the presence of B.In addition, no obvious differences were observed in cracking susceptibility of weld-metal in the four alloys.The cracking modes and mechanisms underlying the effect of B and C addition on weldability could be explained on the basis of microstructures of the four alloys.
M.C.Chaturvedi1，Y.L.WANG1，N.L.Richards1
(1.Department of Mechanical and Industrial Engineering, University of Manitoba Winnipeg, Manitoba R3T 5V6, Canada)
Abstract:Four alloys TMS-75 (Base), Base+B, Base+C and TMD-103 (Base+B+C) with varying levels of B, C were directionally solidified (DS), and their weldability was investigated by bead-onplate electron beam welding.It was found that cracking occurred in the weld-metal, as well as in the heat affected zone (HAZ).Both γ/γ'' and/or γ/carbide eutectic contributed to the weld-metal cracking, and the γ/γ'' eutectic was found to be mainly responsible for cracking in HAZ However, constitutional liquation of carbides seems to have made some contribution also.The B addition had a detrimental effect on HAZ cracking susceptibility, while C addition improved it appreciably even in the presence of B.In addition, no obvious differences were observed in cracking susceptibility of weld-metal in the four alloys.The cracking modes and mechanisms underlying the effect of B and C addition on weldability could be explained on the basis of microstructures of the four alloys.
Key words:Ni-based superalloy; low melting point constituents; liquation cracking;
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