Browsing by Author "Mabhali, Luyolo Andrew Baxolise"

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Effect of dynamic workforce capabilities on firm level innovation in the South African metals industry
(University of the Witwatersrand, Johannesburg, 2024) Mabhali, Luyolo Andrew Baxolise; Mzyece, Mjumo
Increasing employee diversity in gender, age, ethnicity generally has a positive impact on the firm level innovation due to diversification of views and experiences. Employee education is an important factor for innovation since education stimulates the capacity of employees to comprehend, create and process information due to better understating of the theoretical concepts of their trade. On the other hand, employee tenure is associated with experience and employees with a long organisational tenure are more familiar with the processes of the organisation and its strategy. Accumulated work experience, inside and outside the organisation, is also important as experienced employees have developed skills that are relevant and specific to their domain, thereby, tackling problems in a more focused and relevant way. The research outlined in this document proposes to combine attributes such as gender, age and ethnicity into a demographic background factor. The current research investigates the effect of this demographic background factor, together with education qualification and tenure, on firm-level innovation in the South African metals industry. The hypothesis is that these three factors (education qualification, tenure, and demographic background) are dynamic workforce capabilities that influence firm- level innovation in the South African metals industry and warrant consideration in the dynamic capabilities’ literature. The South African metals and engineering sector consists of approximately 10,000 companies that employ over 220,000 blue-collar workers and contributes around 3% of the country’s GDP or R900 billion. It has been facing challenges including production fluctuations and external economic pressures since 2008 but remains a key player in South Africa's industrial landscape. The dynamic capabilities framework is typically applied in environment of rapid change and the organisations in the metal South African metals industry are characterised by legacy machinery and equipment that make up a substantial part of their infrastructure. While the technological changes in other industries are fast-paced, the metals industry is moving at a slower pace. Due to the high numbers of blue- collar workers in this sector, understating the impact of factors such as the three under investigation in this paper could be significant for the industry. iii A positive correlation was found across all three tested factors (education qualification, tenure and demographic attributes) and firm-level innovation. The positive value of the correlation coefficient also showed that a positive change in these three factors results in a positive change in the firm level innovation in the South African metals industry. The conclusions were that dynamic workforce capabilities, which is a combination of education qualification, tenure, and demographic background factors, warrant further consideration to the literature on dynamic capabilities in the context of firm level innovation.
Effect of SiC abrasive breakdown on the wear rate of WC-12wt%Co alloy
(2008-06-25T11:13:28Z) Mabhali, Luyolo Andrew Baxolise
This research project is a preliminary investigation of the effect of SiC abrasive breakdown on the wear rate of a WC-12wt%Co mining alloy. Wear tests were carried out on a two body-sliding wear apparatus under (a) “Ideal” (replacing the SiC paper periodically to ensure continual exposure to fresh abrasives), (b) “No debris” (removing the wear debris periodically) and (c) “With debris” (retaining the wear debris for the entire wear test) wear conditions. The WC-12wt%Co specimens and SiC abrasive grits were examined before and after the wear tests using optical, stereo and electron microscopy. As wear progressed, the SiC abrasives blunted thereby increasing the abrasive/specimen contact area, resulting in a reduction in the WC-12wt%Co wear rate. Wear debris clogging the interstices between the abrasive grits caused a further reduction in the WC-12wt%Co wear rate by adding to the abrasive/specimen contact area already created by blunting. Increasing the applied load resulted in an increase in the WC-12wt%Co wear rate under “Ideal” wear conditions. Under the remaining wear conditions, the increased load resulted in a faster deterioration of the SiC grits. The dominant wear mechanisms under all conditions are characterized by hard abrasive wear that caused extensive grooving, Co binder extrusion and cracking and fragmentation of WC grains.
Laser surface alloying and in-situ formation of aluminium metal composites reinforced with ceramics and intermetallics.
(2012-01-31) Mabhali, Luyolo Andrew Baxolise
This thesis describes the novel laser surface alloying of aluminium AA1200 with various combinations of Ni, Ti and SiC powders, using a 4.4kW Rofin Sinar Nd:YAG laser in order to improve its mechanical and tribological properties. The laser alloying parameters were optimized on the breakdown systems of the complex Al-Ni-Ti-SiC system. Various analytical techniques were used to study the microstructures produced. Wear testing was conducted under sliding and abrasion conditions while the fracture mechanisms were investigated using impact tests. Aluminium surfaces reinforced with metal matrix composites and intermetallic phases were achieved. The phases present depended on the composition of the alloying powder mixture. Al reacted with Ni to form Al3Ni and Al3Ni2 intermetallic phases while Ti reacted with Al to form an Al3Ti intermetallic phase. Some of the SiC particles dissociated and reacted with either Al or Ti to form Al4C3, Al4SiC4, TiC or Ti3SiC2 phases. Si reacted with Ti to form a Ti5Si3 phase. An increase in surface hardness was achieved, up to a maximum of 13 times that of aluminium when alloying with 80wt%Ni + 15wt%Ti + 5wt%SiC. The increase in hardness was attributed to the intermetallic phases especially the Al3Ni2 phase. Alloying led to a 4-38% improvement in the wear resistance of the pure aluminium under sliding wear conditions and a 19-82% improvement under three body abrasion wear conditions. The predominant wear mechanisms for both wear types were groove formation by ploughing and cutting action of the abrasive particles, smearing, material pile-up, extensive cracking of the intermetallic phases and fracturing of the embedded SiC particles in the MMCs. Alloying led to a 31-50% decrease in the impact resistance of the pure aluminium. Brittle fracture of the SiC particles and transgranular cracking of the intermetallic phases were observed for the laser alloyed surfaces while ductile fracture was observed for the bulk aluminium.