Influence of a saline test environment on the Fatigue properties of laser metal deposition Ti-6al-4v specimens
- Authors: Botha, Sheldyn Jaye
- Date: 2021-04
- Subjects: Metal organic chemical vapor deposition , Salines
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/59203 , vital:60304
- Description: This study investigated the effects of the position of extraction and a corrosive environment on the fatigue properties of Ti-6Al-4V Laser Metal Deposition (LMD) specimens. Additive manufacturing (AM) processes allow for a reduction in manufacturing time, whilst constructing complex geometries. AM induces a complex thermal history which influences the microstructure in the material (1). The microstructure affects the fatigue properties where a finer microstructure is more favourable for increasing the fatigue life (2). Fatigue failure is one of the main modes of failure during a material’s service life (3). Thus, it is imperative to investigate the material’s fatigue behaviour. Major parameters of the LMD process were investigated, allowing bulk LMD coupons to be manufactured, from which fatigue specimens were extracted at three different heights. Static properties were attained through tensile testing and a Vickers Micro-Hardness evaluation. These properties allowed for calculating benchmark stresses that were utilised for fatigue testing. The biocompatibility of Ti-6Al-4V makes it desirable for medical implants – the core influence of this study. An implant is constantly subjected to a corrosive saline environment, introducing a corrosive mechanism of failure, known to decrease the life of a material. A rotary bending fatigue platform was utilised as it allowed for modifications to introduce a corrosive saline environment through means of a saline dosing system. Literature reports a higher possibility of corrosion fatigue occurring under rotary bending fatigue conditions for Ti alloy specimens (4,5). The fatigue data indicated no significant effect on the fatigue properties was evident when comparing the position of extraction, attributed to the interrupted build strategy utilised for manufacturing the bulk coupons. The specimens displayed a shift in fatigue life when subjected to a corrosive saline environment. Upon analysis, there was little variation in the microstructures at each position of extraction, attributed to the interrupted build strategy. , Thesis (MA) -- Faculty of Engineering, the Built Environment, and Technology, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Botha, Sheldyn Jaye
- Date: 2021-04
- Subjects: Metal organic chemical vapor deposition , Salines
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/59203 , vital:60304
- Description: This study investigated the effects of the position of extraction and a corrosive environment on the fatigue properties of Ti-6Al-4V Laser Metal Deposition (LMD) specimens. Additive manufacturing (AM) processes allow for a reduction in manufacturing time, whilst constructing complex geometries. AM induces a complex thermal history which influences the microstructure in the material (1). The microstructure affects the fatigue properties where a finer microstructure is more favourable for increasing the fatigue life (2). Fatigue failure is one of the main modes of failure during a material’s service life (3). Thus, it is imperative to investigate the material’s fatigue behaviour. Major parameters of the LMD process were investigated, allowing bulk LMD coupons to be manufactured, from which fatigue specimens were extracted at three different heights. Static properties were attained through tensile testing and a Vickers Micro-Hardness evaluation. These properties allowed for calculating benchmark stresses that were utilised for fatigue testing. The biocompatibility of Ti-6Al-4V makes it desirable for medical implants – the core influence of this study. An implant is constantly subjected to a corrosive saline environment, introducing a corrosive mechanism of failure, known to decrease the life of a material. A rotary bending fatigue platform was utilised as it allowed for modifications to introduce a corrosive saline environment through means of a saline dosing system. Literature reports a higher possibility of corrosion fatigue occurring under rotary bending fatigue conditions for Ti alloy specimens (4,5). The fatigue data indicated no significant effect on the fatigue properties was evident when comparing the position of extraction, attributed to the interrupted build strategy utilised for manufacturing the bulk coupons. The specimens displayed a shift in fatigue life when subjected to a corrosive saline environment. Upon analysis, there was little variation in the microstructures at each position of extraction, attributed to the interrupted build strategy. , Thesis (MA) -- Faculty of Engineering, the Built Environment, and Technology, 2021
- Full Text:
- Date Issued: 2021-04
The effect of human resources management practices on employee commitment: the case of Mnquma Local Municipality
- Fihla, Siphenathi https://orcid.org/0000-0001-9632-2650
- Authors: Fihla, Siphenathi https://orcid.org/0000-0001-9632-2650
- Date: 2018
- Subjects: Personnel management--South Africa , Municipal government--South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24431 , vital:62790
- Description: This study evaluated the relationship between the Human Resource Management Practices (HRMP) and employee commitment. Results based on a sample from Mnquma Local Municipality indicate that these practices have a significant impact on employee commitment. This project will help to advance research on exploring the influence of organisational variables on commitment. Research purpose: The purpose of the study was to investigate the effects of human resources management practices on employee commitment at Mnquma Local Municipality. Motivation for the study: The study examines HRMP and employee commitment in the public sector. The relationship between the two may be of value to the municipality’s success. Research approach, design and method: A quantitative research approach was followed to carry out this study. Data were collected from a sample of 137 respondents in a selected municipality (Mnquma Local Municipality). A self-administered questionnaire was sent to respondents. Main findings: A significant relationship was found between HRMP and employee commitment. Practical or managerial implications: Findings may be relevant to practitioners, including strategic management researchers, policy-makers, directors, managers, and supervisors. The study could assist various practitioners directly or indirectly involved in private and public organisations to develop HRMP that improves employee commitment. Contribution or value-add: The study adds to the literature on HRMP and employee commitment among the public service. , Thesis (MCom) -- Faculty of Management and Commerce, 2018
- Full Text:
- Date Issued: 2018
- Authors: Fihla, Siphenathi https://orcid.org/0000-0001-9632-2650
- Date: 2018
- Subjects: Personnel management--South Africa , Municipal government--South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24431 , vital:62790
- Description: This study evaluated the relationship between the Human Resource Management Practices (HRMP) and employee commitment. Results based on a sample from Mnquma Local Municipality indicate that these practices have a significant impact on employee commitment. This project will help to advance research on exploring the influence of organisational variables on commitment. Research purpose: The purpose of the study was to investigate the effects of human resources management practices on employee commitment at Mnquma Local Municipality. Motivation for the study: The study examines HRMP and employee commitment in the public sector. The relationship between the two may be of value to the municipality’s success. Research approach, design and method: A quantitative research approach was followed to carry out this study. Data were collected from a sample of 137 respondents in a selected municipality (Mnquma Local Municipality). A self-administered questionnaire was sent to respondents. Main findings: A significant relationship was found between HRMP and employee commitment. Practical or managerial implications: Findings may be relevant to practitioners, including strategic management researchers, policy-makers, directors, managers, and supervisors. The study could assist various practitioners directly or indirectly involved in private and public organisations to develop HRMP that improves employee commitment. Contribution or value-add: The study adds to the literature on HRMP and employee commitment among the public service. , Thesis (MCom) -- Faculty of Management and Commerce, 2018
- Full Text:
- Date Issued: 2018
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