Characterization of laser deposited Ti6Al4V/TiC composite powders on a Ti6Al4V substrate
- Authors: Mahamood, R. M. , Akinlabi, Esther Titilayo , Shukla, M. , Pityana, S.
- Date: 2014
- Subjects: Laser metal deposition , Material characterization
- Type: Article
- Identifier: uj:4986 , http://hdl.handle.net/10210/13118
- Description: This paper reports the material characterization of Ti6Al4V/TiC composite produced by laser metal deposition. The Ti6Al4V/TiC composites were deposited with a composition ratio of 50 wt.% Ti64l4V and 50 wt.% TiC. The depositions were achieved by delivering the two powders from a powder feeder consisting of two different hoppers and each hopper contains each of the powders. A total of eight experiments were performed, the scanning speed was kept constant at 0.005 m/s and the laser power varied between 0.4 and 3.2 kW. The gas flow rate and the powder flow rates were also kept at constant settings of 1.44 g/min and 1 l/min respectively for each hopper. The deposits were laterally sectioned, metallographically prepared and characterized through microstructural evaluation, microhardness and wear resistance performance. The effects of varying the laser power on the resulting properties of the composites were studied extensively. The microstructure consists of un-melted carbide (UMC) in the matrix of alpha and prior beta grain structure of Ti6Al4V, and in varying degrees in all the samples. The results showed that the microhardness and the wear resistance performance were dependent on the laser power.
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Laser metal deposition of functionally graded Ti6Al4V/TiC
- Authors: Mahamood, R. M. , Akinlabi, Esther Titilayo
- Date: 2015-06-20
- Subjects: Functionally graded materials , Laser metal deposition , Titanium alloys
- Type: Article
- Identifier: uj:5119 , ISSN 02641275 , http://hdl.handle.net/10210/14077
- Description: Functionally graded materials (FGMs) are advanced materials with improved properties that enable them to withstand severe working environment which the traditional composite materials cannot withstand. FGM found their applications in several areas which include: military,medicine and aerospace. Various manufacturing processes are used to produce functionally graded materials that include: powder metallurgy, physical vapour deposition, chemical vapour deposition process and laser metal deposition process. Laser metal deposition (LMD) process is an additive manufacturing process that can be used to produce functionally graded material directly from the three dimensional (3D) computer aided design (CAD) model of the part in one single process. LMD process is a fairly new manufacturing process and a highly non-linear process. The process parameters are of great importance in LMD process and they need to be optimized for the required application. In this study, functionally graded titanium alloy composite was produced using optimized process parameters for each material combination as obtained through a model that was developed in an initial study and the FGM was characterized throughmetallurgical, mechanical and tribological studies. The results showthat the produced FGM has improved properties when compared to those produced at constant processing parameters for all material combinations.
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Processing parameters influence on wear resistance behaviour of friction stir processed Al-TiC composites
- Authors: Akinlabi, Esther Titilayo , Mahamood, R. M. , Akinlabi, S. A. , Ogunmuyiwa, E.
- Date: 2014
- Subjects: Friction stir welding , Friction stir processing , Materials - Mechanical properties
- Type: Article
- Identifier: uj:4995 , http://hdl.handle.net/10210/13130
- Description: Friction stir processing (FSP) being a novel process is employed for the improvement of the mechanical properties of a material and the production of surface layer composites. The vital role of the integrity of surface characteristics in the mechanical properties of materials has made the research studies into surface modification important in order to improve the performance in practical applications. This study investigates the effect of processing parameters on the wear resistance behavior of friction stir processed Al-TiC composites. This was achieved through microstructural characterization by using both the optical and scanning electron microscope (SEM), microhardness profiling, and tribological characterization by means of the wear. The microhardness profiling of the processed samples revealed an increased hardness value, which was a function of the TiC particles incorporated when compared to the parent material. The wear resistance property was also found to increase as a result of the TiC powder addition. The right combination of processing parameters was found to improve the wear resistance property of the composites produced.
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Revolutionary additive manufacturing : an overview
- Authors: Mahamood, R. M. , Akinlabi, Esther Titilayo , Shukla, M. , Pityana, S.
- Date: 2014
- Subjects: Adaptive control , Additive manufacturing
- Type: Article
- Identifier: uj:4993 , http://hdl.handle.net/10210/13128
- Description: Consumer demands are moving away from standardized to customized products, as such, the evolution of alternative manufacturing techniques has become imperative. Additive manufacturing (AM) is a process of building components layer by layer as against the traditional methods which are subtractive in nature. Though AM offers lots of advantages over traditional manufacturing techniques, its wide application is still however in the infancy phase. Despite all the benefits derived from AM technology, there are still a lot of unresolved issues with the technology that has hindered its performance thereby limiting its application to high tolerant jobs. This paper takes a look at some important AM technologies, some problems currently facing AM technology at large and proposes some solutions to these problems. A major known drawback in AM is poor dimensional accuracy and poor surface finish, only the layer height and melt pool temperature are controlled to solve this problem in the literature. The stair-stepping effect in adaptive manufacturing is rooted in a natural phenomenon of surface tension which is the cause of the poor surface finish and in combination with other factors is responsible for the poor dimensional accuracy. An adaptive controller is proposed for removing stair-stepping effect to improve the dimension accuracy, the surface finish and the mechanical properties of the components. Successful implementation of these proposed controllers will greatly improve the performance of AM technologies and also aid its wide application for end use products. Further research work is also suggested to improve the overall AM performance.
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