Effect of heat input on cracking in laser solid formed DZ4125 superalloy. (December 2016)

• Record Type: Journal Article
• Authors: Hu, Y.L.; Lin, X.; Song, K.; Jiang, X.Y.; Yang, H.O.; Huang, W.D.
• Is Part Of: Optics & laser technology. Volume 86(2016)
• Page Start: 1
• Page End: 7
• Publication Date: 2016-12
• Subjects: Laser solid forming -- Heat input -- Liquation cracking; Optics -- Periodicals; Lasers -- Periodicals; Electronic journals; 621.366
• DOI: 10.1016/j.optlastec.2016.06.008
• Languages: English
• ISSNs: 0030-3992

Abstract

Abstract: DZ4125 superalloy, which processes a high hot cracking sensitivity, is deposited on an as-cast substrate using laser solid forming (LSF) in order to investigate the effect of heat input on the cracking in the deposit and the heat affected zone (HAZ) in the substrate. It is shown that the liquation cracks occurred in LSFed sample with the lower heat input. The propagation extent of the cracks can be reduced with increasing the heat input. The crack-free deposits are achieved when the heat input reaches 150 J/mm. The variation of the residual stress in the LSFed sample with the heat input are discussed based on the micro-indentation analysis. It can be found that the elimination of the cracks with the high heat input can be attributed to the lower temperature gradient and thermal stresses in the LSFed sample. Besides, the backfilling of the liquid melt from the molten pool to the crack is also observed with the high heat input, which is also beneficial to the healing of crack in the HAZ of the molten pool. Highlights: The characteristics of liquation cracks. The evolution of cracks with the heat input variation. The measurements and mechanism to control the cracks.