Search

Your search keyword '"Pityana, Sisa"' showing total 251 results
Start Over Author "Pityana, Sisa"
251 results on '"Pityana, Sisa"'

1. CFD MODEL OF LASER ADDITIVE MANUFACTURING PROCESS OF CYLINDERS

Author

Tamsaout, Toufik, Kheloufi, Karim, Amara, El Hachemi, Arthur, Nana Kwamina, and Pityana, Sisa

Subjects
laser additive manufacturing, ti-6al-4v cylindrical coupons, cylindrical geometry, Industrial engineering. Management engineering, T55.4-60.8
Abstract

A theoretical approach based on a numerical simulation using experimental data is proposed as a contribution to the study of laser-based additive manufacturing by direct energy deposition (DED). The aim is to simulate the stages of layer-by-layer build-ups by considering the induced generated liquid metal in a cylindrical geometry. For normal atmospheric conditions, a 3D model is developed using the finite volumes method to solve the governing equations of the occurring fluid flows and heat transfers. The model is based on the experimental work performed on the LENS system at the Council for Scientific and Industrial Research’s (CSIR) National Laser Centre (NLC), where Ti-6Al-4V cylindrical coupons are laser printed and characterised.

Published
2017
Full Text
View/download PDF

2. MICROSTRUCTURE AND MECHANICAL CHARACTERISATION OF TIAL COATED ON Ti64

Author

Masina, Bathusile, Lengopeng, Thabo, Pityana, Sisa, and Tlotleng, Monnamme

Subjects
tial, ti64, tial alloy, laser, scanning electron microscopy, beam scanning speed, Industrial engineering. Management engineering, T55.4-60.8
Abstract

In this study, TiAl alloy was coated on Ti64 using a 1074nm high power continuous-wave laser while varying the laser beam scanning speed. This was done in order to increase the thermo-mechanical properties of Ti64. Scanning electron microscopy (SEM), light optical microscopy, and Vickers’ micro-hardness were used to characterise the clad for macrostructure, composition, and hardness respectively. The macro- and micrographs of the clads indicated a needle- and dendritic-rich structure for the clads and widmanstatten structure at the interface for all the scanning speeds. The overall hardness was found to be high at low scanning speed.

Published
2017
Full Text
View/download PDF

22. Mechanical Properties of a Laser Deposited Spherical Ti4822 Alloy

Author

Tlotleng, Monnamme, Skhosane, Samuel, Pityana, Sisa, Peng, Zhiwei, editor, Hwang, Jiann-Yang, editor, Downey, Jerome P., editor, Gregurek, Dean, editor, Zhao, Baojun, editor, Yücel, Onuralp, editor, Keskinkilic, Ender, editor, Jiang, Tao, editor, White, Jesse F., editor, and Mahmoud, Morsi Mohamed, editor

Published
2020
Full Text
View/download PDF

41. Microstructure and Micro-Hardness Properties of In-Situ LENS Fabricated Ti-Al-Si-xV Alloys

Author

Raji Sadiq Abiola, Popoola Abimbola Patricia Idowu, Pityana Sisa, Popoola Olawale Muhammed, and Tlotleng Monnamme

Subjects
Engineering (General). Civil engineering (General), TA1-2040
Abstract

This study presents laser in-situ alloying of Ti-Al-Si-xV alloys fabricated using the laser engineered net shaping (LENS) machine from elemental powders. The as-built samples were subjected to heat treatment at 1200°C, 1300°C, and 1400°C for 1 hour and furnace cooled (FC) with subsequent homogenization heat treatment at 950°C for 6 hours and FC. The microstructure was characterized by scanning electron microscopy (SEM) equipped with an electron dispersion spectroscopy (EDS). The micro-hardness properties were evaluated with the Vickers hardness tester. The results showed that alloying via in-situ powder deposition followed by heat treatment is practicable for the producing TiAl-based alloys with improved mechanical properties.

Published
2022
Full Text
View/download PDF

42. Post-processing of direct metal deposited AlCrCoCuFeNi HEA using centrifugal barrel finishing

Author

Modikwe Thembisile, Maledi Nthabiseng, Mathe Ntombi, Pityana Sisa, Dada Modupeola, and Makoana Washington

Subjects
Engineering (General). Civil engineering (General), TA1-2040
Abstract

Stainless steels, Ni-based alloys, Ti-based alloys, and more recently high entropy alloys have been used in the aerospace industry to improve the exterior properties of components and coatings that require a fine surface finishing with over high temperature range. High- entropy alloys (HEA) have become a ground-breaking research field that provides solutions for structural/ functional materials in the aerospace industry. These alloys, fabricated via direct metal deposition, have better properties than those produced by arc melting. However, the poor surface finish acquired by the layer-by-layer laser deposition process fails to meet the industrial requirements. The implementation of surface treatment by centrifugal barrel finishing is employed to improve the surface roughness of AlCoCrCuFeNi laser deposited HEA. The results have shown a minimum surface roughness decrease of 40%. Thus, an improved surface finish was achieved.

Published
2022
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results