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Effect of Selective Laser Melting Process Parameters and Heat Treatment on Microstructure and Properties of Titanium Alloys Produced from Elemental Powders
摘要： This work investigates Selective Laser Melting (SLM) process as a method of in-situ synthesis of Ti-5Al and Ti-6Al-4V alloys using elemental powder mixture. Elemental spherical powders were used to prepare a powder mixture and the samples were produced by SLM process using different volume energy densities. The effects of volume energy density on the samples’ relative density, chemical composition, microstructure and microhardness before and after heat treatment have been studied. It was shown that volume energy density significantly effects the density and microstructure of Ti-5Al and Ti-6Al-4V alloys, as well as, the microhardness of obtained Ti-6Al-4V.
关键词： additive manufacturing,in-situ synthesis,titanium alloy,powder bed fusion,elemental powders
更新于2025-09-16 10:30:52
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Optimization of Process Parameters Using Surface Response Methodology for Laser Welding of Titanium Alloy
摘要： Laser beam welding input conditions are greatly influence the quality of the welded joints and they have significant role on the controlling of their strength and metallurgical properties. The metallurgical properties and weld bead geometry and mechanical properties of the joints determine the quality of the joints. In this study, the fusion zone width, penetration, width of the heat affected zone and strength of the titanium alloy welds were investigated using laser welding process. The surface response methodology design is carried out for the experimental design by the development of regression equations. Analysis of variance (ANOVA) was used to check the validity of the model. In order to identify the significant parameters, student’s test is conducted. The obtained results from response surface methodology were compared with the experimental results and validated.
关键词： Optimization,Fusion zone,Mechanical properties,Laser welding,Welding parameters,Titanium alloy,Bead geometry
更新于2025-09-16 10:30:52
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Effect of Process Parameters and Heat Input on Weld Bead Geometry of Laser Welded Titanium Ti-6Al-4V Alloy
摘要： Laser beam welding is one of the most favorable welding technique and its importance in industry is demanding due to higher welding speeds and lower dimensions and distortions in the welds. Moreover, its high strength to weld geometries and minimal heat affected zones makes favorable for various industrial applications. In the present study, laser welding of titanium alloy was investigated to observe the effects of parameters on the bead geometry and metallurgical properties. The laser power and welding speeds were varied to identify their impact on the formation of weld geometry. The width and depth of the fusion zone is varied with welding conditions. The finer grains identified in weld zone and the width of heat affected zone was significantly changes with laser welding power. The mechanical properties of the weld joint are controlled by obtaining optimum weld bead geometry and width of the head affected zone in the welds.
关键词： Heat input,Fusion zone,Microstructure,Mechanical properties,Laser welding,Microhardness,Weld bead geometry,Titanium alloy
更新于2025-09-16 10:30:52
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Machinability of titanium alloy through laser machining: material removal and surface roughness analysis
摘要： Laser milling is a competent precision process especially when the work material is hard-to-machine such as titanium alloys. While performing the laser milling, a slight change in one of the laser parameters results in an abrupt change in the machining outcomes. A close match between the designed and the machined geometries is the essence of precision machining. A precise control over the material removal rate per laser scan is highly desirable but difficult to achieve. The difficulty level becomes higher if high surface finish is desired alongside the precision machining. In this research, the objective was set to perform the laser milling on titanium alloy (Ti-6Al-4V) with 100% control over material removal rate (MRR) per laser scan and minimum surface roughness (SR). Influence of the five laser parameters (laser intensity, pulse frequency, scan speed, layer thickness, and track displacement) on MRR and SR has been deeply investigated. Significance of each laser parameter is evaluated through ANOVA. Mathematical models for both the responses are developed to estimate the resulting responses at any parametric setting. Models have also been validated through confirmatory tests. Optimization of laser parameters is of great importance to remove the material exactly equal to the desired depth with minimum surface roughness. Therefore, the optimized combinations of laser parameters have been proposed which ensure the conformance of 100% MRR and minimum surface roughness with composite desirability > 0.9. Confirmatory experiments revealed that the optimized parameters are capable to produce the laser milling results as per the models’ predicted results. Additionally, the microstructure of the subsequent layers below the milled area has also been examined and compared with the microstructure of the bulk Ti-6Al-4V. By the use of optimized parameters, microstructure of the sub-layers remains unchanged as compared with the microstructure of the base metal. No evidence has been found altering the microstructure of the sub-layers.
关键词： Laser milling,Titanium alloy,Mathematical model,Surface roughness (SR),Optimization,Material removal rate (MRR)
更新于2025-09-16 10:30:52
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Selective Laser Melting of Nanocomposite Ti-6Al-4V and TiC Powder
摘要： The paper presents the study results of the selective laser melting process of the Ti-6Al-4V alloy and nanosized powder TiC composition. The results of the particles morphology study of resulting powder composition after blending are presented. The microstructure and mechanical characteristics of the obtained composite material were studied. Study of microstructures using optical and electron microscopes were conducted.
关键词： Titanium Alloy Composite,Powder Metallurgy,Selective Laser Melting,TiC,Nanopowder
更新于2025-09-16 10:30:52
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Surface Design Using Laser Rapid Manufacturing for Ti64-Hopeite Orthopedic Implants
摘要： Although hopeite bioceramic coatings have already proven effective for achieving better osseointegration and antibacterial character, but the detachment of hopeite coatings during implanting of coated implants can negatively affect the hopeite bioactivity in the physiological environment. To overcome this issue, the present research work proposes a new process route of laser rapid manufacturing (LRM) for depositing hopeite coatings with the metallurgical bond. Microstructure, phase composition, microhardness, antibacterial efficacy, and bioactivity were evaluated using scanning electron microscope, X-ray diffraction, Vickers microhardness tester, fluorescence-activated cell sorting technique, simulated body fluid immersion test respectively. The promising results obtained from these characterizations and testing establishes a new process route LRM as an effective alternative to deposit multifunctional hopeite coatings on metallic prosthetic–orthopedic implants.
关键词： Hopeite,Multifunctional orthopedic coatings,Laser rapid manufacturing,Implant,Laser surface modification,Titanium alloy
更新于2025-09-16 10:30:52
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A contribution to laser cladding of Ti-6Al-4V titanium alloy
摘要： A wear resistant coating was successfully made on an annealed Ti-6Al-4V titanium alloy by laser surface cladding using 60 wt.% WC + wt.% 40 NiCrBSi powder blends. Coaxial laser cladding was performed by means of Yb:YAG disk laser with a 3-KW continuous wave. Different laser interaction times were attempted to get the optimal conditions for promising mechanical properties. The new contribution was to accomplish larger clad layer thickness with applying the shortest possible laser interaction time that can achieve superior clad layer properties. This will decrease energy consumption with an expected money saving which is an essential factor for successful engineering solutions. A high powder ?ow rate of 20 g.min(cid:1)1 was intended in order to obtain a thick, nonporous and crack free clad layer. The clad samples were subjected to thorough microstructure investigations, in addition to microhardness and wear evaluation. The coating so produced exhibits multiple hardness values and exceptional wear resistance under adhesive/sliding wear conditions. The obtained results expose clad layer with superior quality that was achieved at a laser interaction time of 0.3 s. An enhancement in the microhardness values of the clad layers by more than fourfold was attained and the wear resistance was thus signi?cantly improved.
关键词： coaxial laser cladding process,titanium alloy,laser powder cladding,laser interaction time,microhardness,laser surface treatment,wear resistance
更新于2025-09-12 10:27:22
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Laser metal deposition of Ti-6Al-4V alloy with beam oscillation
摘要： One of the most prevalent problems of additive technologies is the improvement of process efficiency at the expense of increase in mass deposition rate and reduction of postprocessing time. Deposition rate can be improved by the modification of the shape and size of the molten pool through the optimization of laser beam power distribution. Time and cost of postprocessing depend on the surface roughness requirements and presence of macroscopic waviness. Beam oscillation can help to solve this problem. Laser metal deposition with linear beam oscillation was studied. Effects of numerous process parameters on pool shape and size was analysed by simulation. The heat conduction problem was solved analytically by Green’s function method. Temperature fields due to moving normally distributed strip heat sources were studied. It was established that on increasing the oscillation amplitude up to laser beam radius the heat flux of normally distributed strip heat source decrease rapidly to 53%. Greater the beam radius, the less effect of amplitude on the peak value of molten pool width and lower allowable oscillation amplitude. Microscopic examination revealed that beam oscillation promotes obtaining smooth wall surface without any macroscopic waviness.
关键词： surface waviness,titanium alloy,beam oscillation,temperature field,laser metal deposition
更新于2025-09-12 10:27:22
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Two pass laser welding of TC4 Titanium alloy to 301L stainless steel via pure V interlayer
摘要： Pulsed laser welding of TC4 Titanium alloy to SUS301 L stainless steel with V sheet as inter-layer was applied. V does not form any intermetallic compound with Ti and Fe. V is used as an interlayer for joining Titanium alloy and stainless steel that the laser successively focused near the Titanium alloy-V and V-stainless steel interfaces. In this way, only two weld zones and unmelted V interlayer can be produced, but also by microstructure of residual solid V interlayer situated between two separately formed weld zones. The unmelted V interlayer acted as a barrier to mixing of the two base materials. The unmelted part of V interlayer also acted as a diffusion barrier between Ti and Fe to avoid the Ti-Fe intermetallics. The tensile strength of joint was 587 MPa accordingly.
关键词： Microstructure,Weld zone,Welding,TC4 Titanium alloy,SUS301L stainless steel,V Interlayer
更新于2025-09-12 10:27:22
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Stress distribution in laser metal deposited multi-layer thick-walled parts of Ti-6Al-4V
摘要： The laser metal deposition is an additive manufacturing technology enabling the production of large scale complex parts without additional treatment like welding or machining. The study of the origin of the stress field during laser metal deposition is essential for solving a number of problems, including: the assessment of cold and hot cracking; prediction of the fatigue resistance, and the stress corrosion cracking. The quantitative study of transient and residual stresses in build parts is necessary for optimising the parameters of processing and post-production stress relieving heat treatment. Residual stress field in laser metal deposited 50-layer (4-pass per layer) wall of Ti-6Al-4V was analysed experimentally using neutron diffraction and numerically using finite element simulation. Long dwell time between passes and a rigid substrate was used in order to simulate conditions of large scale parts fabrication. An analysis of the calculated and experimentally measured residual stress field showed that near the edges of the buildup there is a region where all three components of stress field are tensile, and normal stress exceeds the yield stress by more than 25%. Moreover, normal plastic strain in this area are also tensile and reaches 2.5-3%. The longitudinal tensile stress closes to yield stress on almost the entire length of the several last layers near the top of the buildup. Residual stress field calculated using neutron diffraction data according to interplanar lattice distance obtained assuming plane stress approach has a satisfactory agreement with FE simulated results.
关键词： Neutron diffraction,Laser metal deposition,Simulation,Residual stress,Titanium alloy
更新于2025-09-12 10:27:22