Effect of scanning speed and powder flow rate on the evolving properties of laser metal deposited ti-6al-4v/cu composites
- Authors: Erinosho, Mutiu F. , Akinlabi, Esther Titilayo , Pityana, Sisa
- Date: 2016
- Subjects: Hardness , High pfr , Laser metal deposition , Microstructure , Porosity , Volume of deposited composite
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/93307 , uj:20331 , Citation: Erinosho, M.F., Akinlabi, E.T. & Pityana, S. 2016. Effect of scanning speed and powder flow rate on the evolving properties of laser metal deposited ti-6al-4v/cu composites.
- Description: Abstract: In Laser Metal Deposition (LMD), good bonding between two similar or dissimilar materials can be achieved if the interrelationships between the processing parameters are well understood. LMD samples of titanium alloy, Ti-6Al-4V and copper, Cu were produced by varying the scanning speed and keeping other parameters constant. The deposited samples were characterized through the volume of deposited composites, microstructure, microhardness and the degree of porosity. The effect of the optimized high (powder flow rate) PFR, scanning speed varying from 0.06 m/min to 1.2 m/min and a constant power of 1kW led to a degree of porosity on the deposited composites. The varying percentages of porosities in the samples have an advance merit effect in the implantation of bones in animal and human. It was found that the existence of pores reduced as the scanning speed increases. The Vickers mirohardness was observed to increase with an increase in the scanning speed which shows an improvement in the properties of the Ti-6Al-4V/Cu composites. At low scanning velocity, the microstructure appears coarse due to the high rate of powder deposited at the same power of 1kW. The α-phase acicular microstructure decreases in size and thickness with an increase in the scanning speed. Widmanstätten structure was found in the scanning electron microscopy analyses. The results show that high PFR and low scanning speed have significantly influenced the evolving properties of the deposited composites.
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On heat treatment and surface characterization of spark Eeroded nickel-based superalloy developed by additive manufacturing
- Authors: Khan, Adam M. , Gupta, Kapil
- Date: 2020
- Subjects: Electron microscopy , Hardness , Laser sintering
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/411167 , uj:34541 , Citation: Khan, A.M. & Gupta, K. 2020. On heat treatment and surface characterization of spark Eeroded nickel-based superalloy developed by additive manufacturing.
- Description: Abstract: In this study, a nickel-based superalloy Inconel 718 material was developed through direct metal laser sintering process. To enhance the mechanical properties, printed material is heat treated at two different conditions in the combination of solution and aging. The transformation of microstructure from original anisotropic phase are studied using optical microscope. The change in mechanical properties were evaluated. The hardness of the heat- treated samples obtained are 35HRC and 39HRC for the heat treatment plan at 1100˚C + 845˚C and 980˚C + 720˚C (solution + ageing) respectively. Further, micro holes were machined on these two material samples using spark erosion micro machining or micro electric discharge machining (µEDM) process. Applied voltage, capacitance, and material hardness were three major variable parameters. Experiments are performed with hollow tungsten carbide rod of 300µm in diameter as a drill tool rotating at a speed 1500rpm for a constant machining time of 30min. Optical and scanning electron micrographs have been used to analyse the hole quality and therefore the performance of µEDM. Perfect concentric drill hole was produced with 35HRC sample than the other. Weld spatters and metal drops found around the surface of 39HRC sample. The range of drill hole varies to a maximum of ϕ385µm in low hardness and ϕ400µm in high hardness samples. The depth of drill hole is maximum with high hard sample at l00V and 100nF process condition. Light spectroscope – based roughness characterization revealed the minimum surface roughness measured was 6.946µm in low hard and 9.829µm in high hard material.
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