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EBSD characterization of the L-605 Co-based alloy welds processed by pulsed Nd:YAG laser welding
摘要： Herein, pulsed Nd:YAG laser welding of the L-605 Co-based alloy was investigated. The effect of the welding heat input (HI) on the penetration depth, microstructure, and mechanical properties of the weld metal was studied. A field emission scanning electron microscopy equipped with an electron backscatter diffraction (EBSD) detector was used to perform microstructural characterization. The results indicated that use of the HI value in the range of 48–80 J/mm could result in the formation of sound welds with full penetration depth at bead-on-plate configuration. EBSD studies revealed that when a low HI value was used to fabricate the double-welded sample, the {1 0 0} direction of austenite grains in the weld metal was parallel to the transvers and welding directions. Regarding the single-welded sample with a high HI value, the ?1 0 0? direction was strongly oriented at an angle between 40° to 50° with respect to the welding direction. Improvement in the hardness of both single-welded and double-welded samples was observed, as compared to the based metal. The results of tensile tests showed that tensile strength of the weldments was higher or almost similar to that of the base metal. Overall, the changes in the HI values had no significant effect on mechanical behavior of the weldments.
关键词： EBSD analysis,Microstructure,Laser welding,Mechanical behavior,Co-based alloy
更新于2025-09-23 15:21:01
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Water cooling assisted laser dissimilar welding with filler wire of nickel-based alloy/austenitic stainless steel
摘要： To clarify the e?ects of water cooling on solidi?cation behavior of pulsed laser welding of Nickel-based alloy/austenitic stainless steel with ?ller wire, and to improve the mechanical properties of laser welded joints, the analyses of morphology, microstructure, anti-peel property and micro-hardness were carried out. The results indicated that adding water cooling increased cooling rate and temperature gradient of the weld. And the addition of water cooling made constitutional supercooling of the weld easier, so that the solidi?cation rate increased with the increase of the temperature gradient. Therefore, the weld grain was re?ned by about 28%, and the average width of unmixed zone decreased by 35%, with a low volume fraction of Mo-rich precipitated phase consisting of p phase and μ phase. The μ phase was discovered in laser welding Nickel-based alloy/austenitic stainless. Both p phase and μ phase had a good coherent relationship with the matrix, which resulted in the low phase boundary energy between precipitated phase and matrix. The coherent relationship is described as [1 4 3] p // [5 3 1] γ between the p phase and the matrix. And the coherent relationship is described as [1 2 0] μ // [2 2 1] γ between the μ phase and the matrix. There are the stacking faults in the μ phase along the direction of [1 1 0], which is one of the slip system in μ phase. At the same time coherent relationship between p phase and matrix is better than that of μ phase. The micro-hardness, load capacity per length, and anti-peel stress were improved by 10.5%, 8.1%, and 11.8%, respectively.
关键词： Ni-based alloy,Precipitated phase,Filler wire,Water cooling assisted,Laser dissimilar welding
更新于2025-09-16 10:30:52
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Laser Cladding of Heat-Resistant Iron Based Alloy
摘要： The paper presents the results of the composition, structure and mechanical characteristics of heat-resistant iron based alloy samples produced by laser cladding. The samples were manufactured using secondary raw material (chips), which were converted into powder by plasma spheroidization. The crystalline transformations for the as-processed as well as after several heat treatment conditions were analyzed. Phase, chemical composition and mechanical characteristics were investigated.
关键词： mechanical properties,additive manufacturing,heat-resistant iron based alloy,microstructure,laser cladding
更新于2025-09-16 10:30:52
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The Effect of Laser Power on the Microstructure of the Nb-Si Based <i>In Situ</i> Composite, Fabricated by Laser Metal Deposition
摘要： The Nb-Si in-situ composite samples were fabricated by laser metal deposition additive manufacturing technology from mechanically alloyed powders in vario-planetary ball mill. A laser metal of samples was carried out at various laser powers: 500 W, 1000 W, 1400 W. The microstructure of a sample grown at a laser power of 500 W consists of a solid solution of Nb, Nb3Si, and dendritic chains of Ti. When the laser power is increased to 1000 W, the volume fraction of silicides increases, the structural heterogeneity decreases. With further increase in laser power to 1400 W, Ti dissolves in Nb, dendritic chains disappear, Nb5Si3 silicide stabilizes.
关键词： Additive manufacturing,Nb-Si based alloy,Direct energy deposition
更新于2025-09-16 10:30:52
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A Study of Structure and Morphology of Bulk Metallic Glasses after Laser Beam Treatment
摘要： Recently, the Zr-based bulk metallic glasses (BMGs) have attracted attention because of their good glass-forming ability and excellent mechanical properties. The amorphous structure is thermodynamically unstable, and it tends to change into an equilibrium crystalline state. The objective of this work is to test the influence of the laser beam on the surface structure and morphology of BMGs with zirconium matrix. The material for the examination was Zr55Cu30Ni5Al10 alloy obtained by high-pressure copper mold casting method in the form of a plate in specified dimensions. In this paper, irradiation with single impulse and laser beam welding emitted in a pulsed mode which consists of a series of overlapping point interactions were used. Different parameters of the laser beam were employed. Microscopic observations proved that after laser treatment amorphous-crystalline structure appears in the heat-affected zone (HAZ). High-resolution transmission electron microscopy analysis of irradiated metallic glass showed that small amount of crystalline Zr2Ni-type phase was produced in the HAZ, whereas in the fusion zone and parent material amorphous structure appears. What is more, it has been observed that the higher laser beam frequency and energy the more weld penetration takes the shape of an ellipse.
关键词： Zr-based alloy,bulk metallic glasses,laser melting,surface morphology
更新于2025-09-12 10:27:22