Scanning speed and powder flow rate influence on the properties of laser metal deposition of titanium alloy

Abstract: Ti4Al4V is an important aerospace alloy because of its excellent properties that include high strength to weight ratio and corrosion resistance. In spite of these impressive properties processing titanium is very challenging which contributes to the high cost of the material. laser metal deposition, an important additive manufacturing method is an excellent alternative manufacturing process for Ti6Al4V. The economy of this manufacturing process also depends on the right combination of processing parameters. The principal aim of this study is to know the optimum processing parameters that will result in deposit with sound metallurgical bonding with the substrate with proper mechanical property and better surface finish. This will help to reduce the need for expensive secondary finishing operations using this manufacturing process. This study investigates the influence of scanning speed and the powder flow rate on the resulting properties of the deposited samples. Microstructure, Microhardness and surface finish of Ti6Al4V samples that were produced using the laser metal deposition process over a range of scanning speeds, ranging from 0.02 to 0.12 m/s and powder flow rate of ranging from 0.72 to 6.48 g/min..

Influence of scanning speed on the intermetallic produced in-situ in laser metal deposited TiC/Ti6Al4V composite

Abstract: Effect of scanning speed on titanium aluminide-Ti3Al produced in-situ during laser metal deposited TiC/Ti6Al4V has been investigated and its effect on microhardness and wear resistance properties has been studied. In this study, titanium alloy –Ti6Al4V (an important aerospace alloy) was deposited in combination with titanium carbide-TiC using laser metal deposition process. The laser power was maintained at 3.2 kW throughout the deposition process. The powder flow rate and the gas flow rate were also kept at constant values of 2.88 g/min and 2 l/min respectively. The scanning speed was varied between 0.015 and 0.105 m/s , and the influence of the scanning speed on the titanium aluminide (Ti3Al) produced in-situ was studied and its effect on the wear resistance behaviour was also investigated. The study revealed that as the scanning speed was initially increased, the Ti3Al produced in-situ was found to increase and the wear resistance was found to improve. As the scanning speed was further increased beyond 0.06 m/s, the Ti3Al produced and the wear resistance were found to decrease

Manufacturing of aluminium composite materials : a review

Abstract: Aluminium composite materials are becoming very popular as a result of their physical and mechanical characteristics, which are making them relevant to various applications. The addition of reinforcement materials with unique characteristics into aluminium produces aluminium composites with superior quality. Wear resistance, stiffness, strength and hardness are some of the improved properties obtained when reinforcement materials were added to the primary aluminium. This chapter presents some of the manufacturing processes of aluminium, its alloys and composites. The effects of reinforcements on aluminium composites from existing work and research direction on the fabrication of aluminium composite materials were discussed in this chapter

Effect of scanning speed and gas flow rate on surface roughness of LMD titanium-alloy

Abstract: This study investigated the effect of scanning speed and gas flow rate on surface finish produced during the laser metal deposition process of Ti6Al4V, an important aerospace alloy. In this work, Nd-YAG laser was employed with coaxial powder deposition nozzle attached to the end effector of a Kuka robot. The laser power was maintained at 3.0 kW and the powder flow rate at a value 2.88 g/min. The scanning speed was varied between 0.01 and 0.05 m/s and the gas flow rate was varied between 1 and 5 l/min. A total of ten samples were produced and the surface roughness was measured using the average of five measurements from each sample. The microstructure was also studied with optical microscope to relate it to the surface roughness. The results showed that, the average surface finish increased as the scanning speed was increased. Conversely, as the gas flow rate was increased the average surface roughness was reduced. In optimizing the laser metal deposition process, the processing parameters need to be optimized. The results from this study will assist in choosing the right powder flow rate and scanning speed especially in applications such as repair and surface modification

Effect of laser power and powder flow rate on dilution rate and surface finish produced during laser metal deposition of titanium alloy

Abstract: The influence of processing parameters on the resulting properties of laser metal deposition process cannot be overemphasized. In this research, the influence of laser power and powder flow rate on the dilution and surface roughness value produced are critically studied.. The laser power was set between 1.8 kW and 3.0 kW, while the powder flow rate was set between 2.88 and 5.76 g/min. The scanning speed and the gas flow rate were maintained at constant values of 0.05m/s and 4l/min respectively. The study revealed that, as the laser power was increased, the degree of dilution increases but the average surface roughness value decreases. Also, as the powder flow rate was increased, the dilution decreases and the average surface roughness increases. The study shows that it is important to keep the powder flow rare low so as to achieve a better surface finished and also not to use too high laser power as this will result in higher dilution, which is not desirable in the laser additive manufacturing process because it will affect the dimensional accuracy of the part under processing

Gas flow rate and powder flow rate effect on properties of laser metal deposited Ti6Al4V

Tracks of Ti6Al4V powder were deposited on Ti6Al4V substrate using Laser Metal Deposition (LMD) process, an Additive Manufacturing (AM) manufacturing technology, at a laser power and scanning speed maintained at 1.8 kW and 0.005 m/s respectively. The powder flow rate and the gas flow rate were varied to study their effect on the physical, metallurgical and mechanical properties of the deposits. The physical properties studied are: the track width, the track height and the deposit weight. The mechanical property studied is the Microhardness profiling using Microhardness indenter at a load of 500g and dwelling time of 15 μm. The metallurgical property studied is the microstructure using the Optical microscopy. This study revealed that as the powder flow rate was increased, the track width, track height and the deposit weight were increased while as the powder flow rate was increased, the track width, track height and the deposit weight decreased. The results are presented and discussed in detail

Characterizing the effect of processing parameters on the porosity of laser deposited titanium alloy powder

Laser Metal Deposition (LMD) is an additive manufacturing technique that produces parts layer by layer directly from the Computer Aided Design (CAD) file. Highly customized parts with complex shapes such as medical implants can well be manufactured using the LMD process. LMD has been used to produce a wide range of patient specific (customized) parts. Porous parts are of particular importance as medical implants because they can potentially aid the healing process and proper integration of the implant with the body tissues. In this research porous samples of titanium alloy (Ti6Al4V) were produced using the LMD process. Spherical shaped Ti6Al4V powder of particle size ranging between 150 to 200 μm was used. The effect of laser power and scanning speed on the shape, size and degree of porosity of the deposited tracks was investigated. The results showed that as the laser power was increased and the scanning speed decreased, the degree of porosity was reduced. The size of the porosity was also found to reduce as the laser power was increased

Functionally graded material: an overview

Functionally Graded Material (FGM) belongs to a class of advanced material characterized by variation in properties as the dimension varies. The overall properties of FMG are unique and different from any of the individual material that forms it. There is a wide range of applications for FGM and it is expected to increase as the cost of material processing and fabrication processes are reduced by improving these processes. In this study, an overview of fabrication processes, area of application, some recent research studies and the need to focus more research effort on improving the most promising FGM fabrication method (solid freeform SFF) is presented. Improving the performance of SFF processes and extensive studies on material characterization on components produced will go a long way in bringing down the manufacturing cost of FGM and increase productivity in this regard

Laser metal deposition of Ti6Al4V : a study on the effect of laser power on microstructure and microhardness

The effect of laser power on the resulting microstructure and microhardness of laser metal deposited Ti6Al4V powder on Ti6Al4V substrate has been investigated. The tracks were deposited using 99.6 % pure Ti6Al4V powder of particle size ranging between 150 - 200 μm on 99.6% Ti6Al4V substrate. The laser power was varied between 0.8 - 3.0 kW while the scanning speed, powder flow rate and the gas flow rate were kept at the values of 0.005 m/sec, 1.44 g/min and 4 l /min respectively. The microstructure and the microhardness were studied using the optical microscope and the Vickers hardness tester respectively. Layer band or macroscopic banding was observed in all the samples which is phenomenon as it was only reported in the literature for multi-layer deposits. The literature attributed re-melting of the previous layers by the succeeding layers as being responsible for their formation. This study has revealed that this band could be as a result of shrinkage happening in the fusion zone as a result of the interaction of the deposited powder and the melt pool created by the substrate material. This study also reveals the relationship between the microstructure, the average microhardness and the laser power which are comprehensively discussed. The higher the laser power, the lower the density of columnar prior beta grain structure. Also the average microhardness increases as the laser power increases

Laser metal deposition of titanium aluminide composites : a review

Abstract: Development of additive manufacturing (AM) from three dimensional printers with ability of producing parts having no need for tooling continue to wax stronger in the manufacturing field. Laser metal deposition, a technique in AM is usually employed to create solid components from model of computer aided design (CAD). Feeding powder supported by shielding gas employed by this technique, is injected into a melt pool produced by accurately focused laser beam on a substrate. This paper discusses some of the AM technologies available, review on laser metal deposition of titanium aluminide on other metals and alloys, relationship between the processing parameters and structural and mechanical propertie