Effect of Annular Laser Metal Deposition (ALMD) Process Parameters on Track Geometry and Thermal History on Ti6Al4V Alloy Clad

• Published in: Materials Vol. 16; no. 11; p. 4062
• Main Authors: Zhang, Jinchao, Cao, Yupeng, Wang, Heng, Shi, Tuo, Su, Boyong, Zhang, Lei
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 30.05.2023; MDPI
• Subjects: annular laser beam; Clad metals; Cooling rate; Crystal defects; Experiments; Gas flow; Geometry; Height; Laser deposition; laser metal deposition; Lasers; Microhardness; Microstructure; Morphology; Process parameters; Raw materials; Robots; Scanning; Shape effects; Solidification; thermal history; Thin walls; Ti6Al4V; Titanium alloys; Titanium base alloys; track geometry; United States > US; thermal history; laser metal deposition; annular laser beam; track geometry; Ti6Al4V
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma16114062

Annular laser metal deposition (ALMD) is a rising technology that fabricates near-net-shaped components. In this research, a single factor experiment with 18 groups was designed to study the influence of process parameters on the geometric characteristics (bead width, bead height, fusion depth, and fusion line) and thermal history of Ti6Al4V tracks. The results show that discontinuous and uneven tracks with pores or large-sized incomplete fusion defects were observed when the laser power was less than 800 W or the defocus distance was -5 mm. The laser power had a positive effect on the bead width and height, while the scanning speed had the opposite effect. The shape of the fusion line varied at different defocus distances, and the straight fusion line could be obtained with the appropriate process parameters. The scanning speed was the parameter that had the greatest effect on the molten pool lifetime and solidification time as well as the cooling rate. In addition, the microstructure and microhardness of the thin wall sample were also studied. Many clusters with various sizes in different zones were distributed within the crystal. The microhardness ranged from 330 HV to 370 HV.