ResearchSpace

Communities in ResearchSpace

Welcome to ResearchSpace, the institutional repository of the CSIR. ResearchSpace is an open access electronic archive collecting, preserving and distributing scholarly digital materials created by the CSIR.

Recent Submissions

Item

Study of phase constituents, microstructural evolution, tensile properties and micro-Vickers hardness of as-cast and water quenched Ti-Mo-Fe alloy

(2025-03) Moshokoa, NA; Makhatha, E; Raganya, Mampai L; Makoana, Nkutwane W; Mkhonto, D; Phasha, M

This study investigates phase constituents, microstructural evolution, tensile properties and micro-Vickers hardness of as-cast (AC) and water quenched (WQ) Ti-Mo-Fe alloys with varying molybdenum and iron contents. Three ternary alloys with Ti-8.6Mo-3.3Fe (TMF4), Ti-13Mo-2.2Fe (TMF5), and Ti-16.5Mo-1.1Fe (TMF6) compositions were designed from three theoretical methods, namely, electron per atom (e/a) ratio, the molybdenum equivalence (Moeq) and the Bo-Md. These alloys were cast using the arc melting furnace operating under inert atmosphere, followed by solution treatment and quenching. Different characterization techniques were used to analyse the microstructural evolution and phase constituents of the alloys XRD patterns of TMF4 and TMF5 samples in both AC and WQ conditions showed the presence of β and α″ phases whereas XRD peaks of TMF6 alloy in both conditions belonged to only β phase. Optical micrographs of all studied alloys in AC and WQ conditions showed only β equiaxed grains with different grain sizes. The EBSD phase maps of WQ TMF5 and TMF6 alloys revealed the presence of ω and β phases. It was illustrated that with an increase in β stability, the ultimate tensile strength (UTS) decreased slightly from 547 MPa to 540 MPa while elastic modulus of TMF5 and TMF6 decreased from 88 GPa to 74 GPa respectively.

Item

Nutritional value, biochemical properties and health benefits of Baobab

(Into Publishing, 2025-07) Akuaku, J; Gwamba, J; Dlamini, Nomusa R; Raheem, D; Tjiurutue, MJ; Kahaka, G; Bultosa, G; Cheikhyoussef, A

Baobab (Adansonia digitata) is an indigenous African tree greatly valued for its numerous different non-timber products, shade and as a component in various agroforestry-, agroecology and mixed-farming practices. Baobab fruit pulp, seeds, leaves, flowers and roots are consumed by many different African communities. In the present climate change scenario, baobab will have a significant role in carbon sequestration to mitigate global warming, as well as in supporting food and nutrition security and income generation for the sub-Saharan regions. Because of their functional bioactive ingredients, baobab-based foods can also play an important role in public health and disease prevention. Different parts of baobab are increasingly used by the food processing industry in the development of functional foods, food supplements and nutraceuticals for the global market.

Item

Nutritional value, biochemical properties and health benefits of Marula

(Into Publishing, 2025-07) Dlamini, Nomusa R; Akuaku, J; Gwamba, J; Raheem, D; Tjiurutue, MC; Kahaka, G; Bultosa, G; Cheikhyoussef, A

Marula is among the indigenous fruit trees that were selected for domestication in Southern Africa region, to improve people's nutritional status and well-being through the development of products with commercialization potential. Marula-based products have also major potential to improve human health.

Item

Numerical analysis of the failure mechanisms of continuous miner’s cutter sleeves for redesign and remanufacture

(2025-03) Onyono, SO; Kyekyere, E; Lindsay, EE; Mswela, N; Olakanmi, EO; Prasad, RVS; Ndeda, R; Motimedi, T; Botes, A; Pityana, Sisa L

Traditional failure analysis employs visual and microscopic examinations to identify modes, causative factors, and mechanisms of component’s damage. This approach is deficient in determining actual stresses and deformation which cause component’s failure; analysing how component’s geometry influence its failure; and assessing the feasibility of the recommended remedial measures to mitigate component’s failure. To address these concerns in failed sleeves of continuous miner’s cutter (CMCs); this study employed ANSYS software for finite element analysis (FEA), analytical calculation for model verification, while simulation findings were validated via microscopic observations. Collar fracture resulted from a high stress concentration (above 200 MPa) along the transition fillet areas while plastic deformation was caused by stresses above 100 MPa. Interactions between the sleeve and the rock seam generated cyclic stresses between 17–25 MPa which caused collar wear. Geometrical redesign of the sleeve collar by increasing fillet radius from 1 to 9 mm reduced stress to 133.03 MPa due to lower stress concentration factor. Surface modification with hybrid composite (TiC10%wt-WC10%wt) exhibited the best wear-resistance experimentally with the stress reduced to 6.8 MPa upon impact. Simultaneous combination of geometrical redesign and surface modification of the sleeve via laser cladding reduced deformation by 16.53 % (from 0.01277 mm to 0.010658 mm) and stress from 379.78 MPa to 116.44 MPa. It is concluded that multi-faceted failure analysis is a comprehensive approach that not only uncovers the failure modes, causes and mechanisms of premature failure of rotary sleeves, but also ascertains the causative stresses and remedial measures to mitigate the failure of CMC’s sleeves.

Item

Scanning strategy for grain size control in the multitrack laser metal deposition for additive manufacturing applications

(2025-12) Khomenko, M; Makoana, Nkutwane W; Ronzhin, D; Pityana, Sisa L

The comprehensive investigation of scanning strategies of the multitrack layers produced by laser metal deposition (LMD) with coaxial powder feeding is presented. The first two steps of the part additive production are optimized using a previously developed hydrodynamic model in search for low waviness and microstructure control. We verify the numerical model for the single-track LMD showing rather good correspondence. The main parameters of the scanning strategy i.e. scanning path, overlap ratio and idle time are optimized for additive manufacturing (AM) applications. We show that the optimal overlap ratio is dependent on processing parameters and multitrack investigation is needed for its estimation. A new method for optimizing layer growth parameters is proposed, which is in the adjusting of the geometry of a single track when the process conditions change instead of searching for new hatch spacing. Feasibility for modifying the average crystalline size and the preservation of the layer geometry and scanning strategy is presented both numerically and in experiments. The possibility of controlling the grain size of similar layers is another step for building parts with a defined quality.