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Autogenous fiber laser welding of 70/30 Cu-Ni alloy plates
摘要： Cupronickel alloys such as 70/30 Cu-Ni have excellent resistance to sea water corrosion and anti-fouling properties, and thus have been widely used for naval and offshore applications. Traditionally, arc welding and brazing processes have been used to weld such materials. In contrast, laser beam welding is a promising technology due to its high productivity, good process flexibility and reliability, and good welding integrity. In the present work, a high power fiber laser system is used to weld 5-mm thick 70/30 Cu-Ni alloy plates in a configuration of butt joints. Then, the laser welded joints are evaluated in terms of microstructures, defects, and mechanical properties (hardness, face and root bend, and tensile) in accordance with the applicable International Organization for Standardization and Defence Standard specifications.
关键词： Tensile Properties,Microstructure,Butt Joint,Cupronickel Alloy,Bend testing,Laser Welding
更新于2025-11-28 14:24:20
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Microstructure and properties of WC reinforced Ni-based composite coatings with Y <sub/>2</sub> O <sub/>3</sub> addition on titanium alloy by laser cladding
摘要： In this study, WC reinforced Ni-based composite coatings with Y2O3 addition were deposited on Ti-6Al-4V titanium substrate by laser cladding. The phases, microstructure, microhardness and wear resistance of the composite coatings were studied by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, microhardness tester and wear tester. The results showed that good metallurgical bonding was achieved between the composite coatings and substrate. The phases mainly were γ -Ni, TiC, TiB2, Ni3B, M23C6 and WC. Most of the WC was dissolved in small pieces of WC during the laser cladding process. The microhardness of the composite coatings was about 3 times that of the titanium substrate and the wear resistance of the composite coatings had a significant increase.
关键词： titanium alloy,microstructure,Laser cladding,Y2O3,WC,Ni-based composite coatings
更新于2025-11-28 14:24:20
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Wear and Corrosion Resistance of Al0.5CoCrCuFeNi High-Entropy Alloy Coating Deposited on AZ91D Magnesium Alloy by Laser Cladding
摘要： In order to improve the wear and corrosion resistance of an AZ91D magnesium alloy substrate, an Al0.5CoCrCuFeNi high-entropy alloy coating was successfully prepared on an AZ91D magnesium alloy surface by laser cladding using mixed elemental powders. Optical microscopy (OM), scanning electron microscopy (SEM), and X-ray diffraction were used to characterize the microstructure of the coating. The wear resistance and corrosion resistance of the coating were evaluated by dry sliding wear and potentiodynamic polarization curve test methods, respectively. The results show that the coating was composed of a simple FCC solid solution phase with a microhardness about 3.7 times higher than that of the AZ91D matrix and even higher than that of the same high-entropy alloy prepared by an arc melting method. The coating had better wear resistance than the AZ91D matrix, and the wear rate was about 2.5 times lower than that of the AZ91D matrix. Moreover, the main wear mechanisms of the coating and the AZ91D matrix were different. The former was abrasive wear and the latter was adhesive wear. The corrosion resistance of the coating was also better than that of the AZ91D matrix because the corrosion potential of the former was more positive and the corrosion current was smaller.
关键词： laser cladding,wear,AZ91D magnesium alloy,high-entropy alloy coating,corrosion
更新于2025-11-21 11:24:58
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Laser Alloying of Surface of Ti-5.5Al-2Zr-1Mo-1?V Titanium near-α-Alloy Prepared Via Melted by Pulsed Laser Radiation TiC Particles
摘要： Laser alloying of the surface of Ti-5.5Al-2Zr-1Mo-1 V titanium near-α-alloy was carried out in order to improve the surface properties. The surface of the titanium alloy was being melted by pulsed laser radiation while TiC alloying powder component was being supplied to the laser irradiation zone. As a result of laser alloying, partial melting of the powder particles of titanium carbide and mixing them with the substrate metal resulted in the formation of new disperse TiC phases in the form of dendrites and highly dispersed phases. It is shown that laser alloying of Ti-5.5Al-2Zr-1Mo-1 V titanium near-α-alloy by pulsed laser radiation leads to a 1.4 times increase in hardness of the surface of the titanium alloy and reduces friction coefficient 1.2 times.
关键词： Tribological tests,Laser alloying,Microstructure,Titanium alloy
更新于2025-11-21 11:20:48
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Surface nanocrystallization of Cu-Cr alloy by a high power density continuous laser beam
摘要： A nanostructured surface layer of (cid:1)300 lm thickness was fabricated on Cu-30Cr (wt%) hypereutectic alloy by a continuous laser beam with high power density (1.08 (cid:3) 107 W/cm2). The average grain size of Cr-rich particles was re?ned to (cid:1)40 nm, and the solid solubility limit of Cr in Cu was extended to 1.96 at. %. Experimental results show that the dispersion of nano-sized Cr-rich spheroids in Cu-rich matrix was attributed to the Brownian motion of Cr-rich spheroids, and the high cooling rate (5.75 (cid:3) 106 K/s) during liquid phase separation which inhibits the collisions between Cr-rich spheroids.
关键词： Solidi?cation,Surface nanocrystallization,Microstructure,Cu-Cr alloy,Laser surface melting
更新于2025-11-21 11:18:25
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Effects of Platform Pre-Heating and Thermal-Treatment Strategies on Properties of AlSi10Mg Alloy Processed by Selective Laser Melting
摘要： The AlSi10Mg alloy was processed by selective laser melting using both hot- and cold-build platforms. The investigation was aimed at defining suitable platform pre-heating and post-process thermal treatment strategies, taking into consideration the peculiar microstructures generated. Microstructural analyses, differential scanning calorimetry, and high-resolution diffraction from synchrotron radiation, showed that in the cold platform as-built condition, the amount of supersaturated Si was higher than in hot platform samples. The best hardness and tensile performance were achieved upon direct aging from cold platform-printed alloys. The hot platform strategy led to a loss in the aging response, since the long processing times spent at high temperature induced a substantial overaging effect, already in the as-built samples. Finally, the standard T6 temper consisting of post-process solution annealing followed by artificial aging, resulted in higher ductility but lower mechanical strength.
关键词： processing temperature,AlSi10Mg alloy,aging treatment,selective laser melting
更新于2025-11-21 11:18:25
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A study of metallurgy and erosion in laser surface alloying of AlxCu0.5FeNiTi high entropy alloy
摘要： AlxCu0.5FeNiTi high entropy alloy coating is synthesized by premixed high purity Cu, Fe, Ni and Ti powders on AA1050 aluminium substrate by laser surface alloying, with the aim to improve microhardness and erosion rate. Phase constituents, microstructure and microhardness were investigated using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Vickers Microhardness tester, respectively. The erosion behavior of AlxCu0.5FeNiTi coating is checked using an air jet erosion setup. SEM images show presence of three regions. Percentage compositions of these regions are evaluated using Energy Dispersive Spectroscopy. XRD analysis of AlxCu0.5FeNiTi coating confirmed that these regions are a mixture of disordered BCC and two FCC solid solution phases. The microhardness of the AlxCu0.5FeNiTi HEA is 18 times that of the AA1050 aluminium substrate. Results show that AlxCu0.5FeNiTi HEA coating has improved erosion resistance.
关键词： Laser Surface Alloying,Microhardness,Microstructure,High Entropy Alloy,Erosion rate
更新于2025-11-21 11:18:25
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Laser welding characteristics of Ti-Pb dissimilar couples and element diffusion in the molten pool
摘要： Laser welding lead metal to titanium or titanium alloy, which is a typical dissimilar welding process, have a great challenge. Couples of Ti-Pb, Ti6Al4V-Pb were welded by a 3kW continuous wave Nd:YAG laser. The influences of process parameters such as laser power and laser beam offset on welding depth were investigated. Microstructure, element distribution and micro-hardness of the welds were tested. The element diffusion characteristics during laser welding of Ti-Pb couple and Ti6Al4V-Pb couple were studied based on the experiments data. Experimental results show laser beam offset is a primary factor for welding titanium alloy and lead metal, and laser power plays a critical role for welding pure titanium and lead metal. A chemical potential calculation model of Ti-Pb-Al ternary alloy was established. The calculation results show that chemical potential of Ti element increases with enhancing Pb content in Ti-Pb-Al ternary system, however, the chemical potential of Ti element decreases with increasing Pb content in Ti-Pb binary system. According to the calculation results, for Ti-Pb-Al ternary system, because of the Al element in the molten pool, the Ti element tends to diffuse into the Al element, and the diffusion driving force of Ti element to the Pb element is weak. Compared with the Ti-Pb binary system and the Ti-Pb-Al ternary system, it is more likely to form a mixed fusion weld for the binary system, and the mass transfer interface phenomenon is more serious for the ternary system, which is consistent with EDS line scan and microhardness testing results.
关键词： Chemical potential,Interface,Microstructure,Lead metal,Titanium alloy,Laser dissimilar welding
更新于2025-11-21 11:18:25
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Laser Welding of Dissimilar Metal Joint of 6061 Al Alloy and Al Matrix Composite
摘要： In this paper, dissimilar metal joints of 6061 aluminum alloy and aluminum matrix composite material are investigated by laser welding. TiB2 particles were added into the lap joint. The welding process, microstructure, and the corrosion properties of welding joints are examined. The results demonstrate that the selected optimization process parameters are laser power 6 kW, welding speed 0.6 mm/s, pulse width 11.5 ms, and laser frequency 4.5 Hz. There are a few obvious pores in the molten pool. Al2Ti, Fe2Si, and Al0.5Fe3Si0.5 are present in the microstructure. During the welding process, some TiB2 particles are decomposed and reacted with molten Al. Other TiB2 particles are nucleated and solidi?ed, and the excess TiB2 particles are pushed to the grain boundaries by molten Al. TiB2 particles are wetted well by molten matrix metal. The corrosion resistance of alloys in di?erent conditions decreased in the following order: the weld beam >6061 Al > AMC.
关键词： aluminum matrix composite,laser welding,TiB2 particles,microstructure,6061 aluminum alloy,dissimilar metal joints,corrosion properties
更新于2025-11-21 11:18:25
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Development of a high strength Al–Zn–Si–Mg–Cu alloy for selective laser melting
摘要： Despite additive manufacturing processes are already widely used in several industrial applications, there are few materials that are specifically designed and optimized for these technologies. Currently, only few Al alloys are available on the market and employed for 3D printing of structural parts. In particular, SieMg bearing alloys are the most common Al alloys for additive manufacturing, featuring high processability but moderate mechanical properties. By this work, we studied the effect of Si addition on the hot cracking susceptibility of a high strength AleZneMgeCu alloy. A preliminary activity has been carried out by blending AleZneMgeCu and AleSieMg powders and analysing their microstructure and properties achieved after selective laser melting. Eventually a new AleZneSieMgeCu alloy has been designed, produced as powder alloy by gas atomization and tested. The microstructure and phase transformations of the new alloy has been investigated by synchrotron X-ray diffraction, differential scanning calorimetry and microscope analysis. The AleZneSieMgeCu alloy processed by selective laser melting featured a relative density of 99.8%, no hot cracks were noticed within the investigated microstructures. The ability of the new alloy to respond to aging starting from both as built and solution annealed conditions has been also evaluated. A good response to direct aging (directly from as built condition) was demonstrated, featuring yield strength and ultimate tensile strength of 402 and 449 MPa, respectively, and hardness of 174 HV after optimized aging at 165 (cid:1)C for 2 h.
关键词： Differential scanning calorimetry,Metal additive manufacturing,Mechanical properties,Synchrotron X-ray diffraction,High strength Al alloy
更新于2025-11-21 11:18:25