Browsing by Author "Goudar, Dayanand M."
Now showing 1 - 5 of 5
Results Per Page
Sort Options
- Effect of cenosphere fillers on mechanical strength and abrasive wear resistance of carbon–glass polyester compositesPublication . Pulikeshi, K. H.; Goudar, Dayanand M.; Kurahatti, R. V.; Pinto, Deesy G.; Pinto, DeesyFabric-reinforced hybrid polymer composites are present in almost every sector of modern life, and most essential areas of research in recent years have focused on glass–carbon fabric with filler material composites. Fabric and fillers are employed in strengthening polymer composites with the aim of improving their mechanical and tribological properties. The primary objective of this investigation was to investigate thetribological and mechanical properties of unfilled and cenosphere-filled carbon–glass-reinforced polyester composite systems, utilizing two types of fabric (glass and carbon) with cenosphere filler in varying weight fractions (0, 2.5, 5, 7.5, 10, and 12.5 wt.%) for both carbon fabric and the cenosphere. The abrasive wear characteristics were evaluated using a stainlesssteel wheel abrasion tester, utilizing silica sand as the abrasive material. Tests were performed at various distances (360–1800 m) and loads (12 N and 24 N). The results show that the wear rate of carbon–glass fabric-reinforced polyester composites differs significantly, with and without cenosphere fillers. Notably, the unfilled composites exhibit the highest wear volume loss, indicating a substantial improvement in wear resistance with the addition of cenospheres. The results reveal that in carbon–glass fabric-reinforced polyester composites, specific wear rate decreases when more cenospheres are loaded. The wear rate was successfully reduced by cenospheresunder silica sand as an abrasive. Compared to unfilled composites, the mechanical properties of filled composites exhibit superior performance. These variations were explained by examining the worn-out surfaces under an SEM and correlating the features observed with the mechanical properties.
- Effect of nickel on the mechanical properties of spray-formed Al-15Si-2Cu alloy at elevated temperaturesPublication . Goudar, Dayanand M.; Alavandi, Mehabubsubahani R.; Bhat, Subraya Krishna; Bommenahalli, Raghukumar; Kurahatti, Rajashekar V.; Pinto, Deesy G.; Raju, K.; Pinto, Deesyat different temperatures was examined and evaluated with that of the as-cast (AC) alloy. The microstructure of SF alloys revealed uniformly distributed spherical shaped primary silicon and eutectic silicon phases along with fine Ni and Cu intermetallic particles dispersed throughout the equiaxed Al matrix. The microstructure of AC alloys consisted of coarse primary Si, flake-type eutectic phase, Cu-rich intermetallics with a complex branched morphology and a network of short strips. The mechanical properties of the alloys were assessed at temperatures of 30◦C, 100◦C, 200◦C and 300◦C. The SF alloys exhibited higher hardness than AC alloys at all temperatures with a maximum increase of 74 % at 30◦C. The hardness of alloys showed a decreasing trend with increasing temperature. The mechanical strength of SF alloys was higher than that of the AC alloys across the entire temperature range from 30◦C to 300◦C with a decrease in ultimate tensile strength (UTS) by 4–6 % at 250◦C. The SF alloys demonstrated a significant increase in UTS (25 % at 30◦C and 40 % at 300◦C) compared to the AC alloys. The Al-15Si-2Cu-2Ni alloy showed highest increase (14.3–18.6 %) and Al-15Si-2Cu-6Ni alloy showed the lowest increase (10.5 % to 14 %) in percent elongation between 30◦C and 300◦C.
- Effect of sintering temperature on the physical and mechanical characteristics of fabricated ZrO2–Cr–Ni–Ce–Y compositePublication . Saini, Brajesh Chandra; Jain, Naman; Rao, Dinesh Kumar; Singhal, Varun; Verma, Akarsh; Goudar, Dayanand M.; Raju, Kandavalli; Pinto, Deesy G.; Pinto, DeesyThe present study investigates the synthesis and characterization of a zirconium oxide (ZrO2)-based metal composite doped with cerium (Ce) and yttrium (Y), using chromium (Cr) and nickel (Ni) as base metals. These constituents were selected for their superior mechanical properties and compatibility with the ceramic phase. High-purity powders were homogenized via high-energy ball milling, followed by cold pressing and sintering in a controlled atmosphere of hydrogen. The sintering process was conducted at temperatures ranging from 850 °C to 1350 °C to examine the evolution of microstructure, grain growth, and densification. Scanning electron microscopy (SEM) revealed a homogeneous distribution of phases, with distinct microstructural features attributed to each element at different sintering temperatures. The experimental results revealed that the composite’s density was increased by 30% and porosity was reduced by 61% at a sintering temperature of 1350 °C. The hardness and flexural strength of composite were found to be 23% and 60% higher at 1350 °C, respectively, compared to that at 850 °C, suggesting enhanced mechanical properties due to cerium and yttrium reinforcement within matrix and efficient doping and phase transformation. Overall, incorporation of cerium and yttrium significantly improved mechanical behavior and phase stability of ZrO2–Cr–Ni composite, highlighting its potential for advanced engineering applications.
- Enhancing the interfacial adhesion and mechanical strength of pultruded ECR–glass fiber composites with nanofiller-infused epoxy resinPublication . Chandra, Poorna; Venkatarayappa, Ravikumar; Chandrashekar, Savitha D.; Raveendra, Kiran; Bhaskararao, Asha P.; Bheemappa, Suresha; Goudar, Dayanand M.; Kurhatti, Rajashekhar V.; Raju, K.; Pinto, Deesy G.; Pinto, DeesyThe effect of the interaction between silica (nS) and hydroxyapatite (nHap) nanomaterials on the characteristics of unidirectional glass-fiber-reinforced epoxy (GF/Ep) composite systems is investigated in this work. The goal of the study is to use these nanofillers to improve the microstructure and mechanical characteristics. Pultrusion was used to produce hybrid nanocomposites while keeping the GF loading at a consistent 75% by weight. The hybrid nanocomposites were made with a total filler loading of 6 wt.%, including nHap, and a nS loading ranging from 2 to 4 wt.%. The mechanical performance of the composite was greatly improved by the use of these nanofillers. Compared to neat GF/Ep, hybrid nanocomposites with 6 wt.% combined fillers exhibited increased hardness (14%), tensile strength (25%), interlaminar shear strength (21.3%), and flexural strength (33%). These improvements are attributed to efficient filler dispersion, enhanced fiber-matrix adhesion, and crack propagation resistance. Incorporating 4 wt.% nS alone improved hardness (6%), tensile strength (9%), tensile modulus (21%), interlaminar shear strength (11.4%), flexural strength (12%), and flexural modulus (14%). FTIR analysis indicated Si-O-Si network formation and increased hydrogen bonding, supporting enhanced interfacial interactions. Ultraviolet reflectance measurements showed increased UV reflectivity with nS, especially in hybrid systems, due to synergistic effects. Impact strength also improved, with a notable 11.6% increase observed in the hybrid nanocomposite. Scanning and transmission electron microscopy confirmed that the nanofillers act as secondary reinforcements within the matrix. These hybrid nanocomposites present a promising material choice for various industries, including marine structural applications and automotive components.
- Influence of Cu addition on the wear behavior of a Eutectic Al–12.6Si alloy developed by the spray forming methodPublication . Goudar, Dayanand M.; Haider, Julfikar; Raju, K.; Kurahatti, Rajashekar V.; Pinto, Deesy G.; Pinto, DeesyIn the present study, the influence of the addition of copper (Cu) on the wear behavior of a Al-12.6Si eutectic alloy developed using the spray forming (SF) method was discussed, and the results were compared with those of as-cast (AC) alloys. The microstructural features of the alloys were examined using both optical and the scanning electron microscopy, and the chemical composition and phase identification were achieved by X-ray diffraction (XRD) analysis. The results revealed that the microstructure of binary the SF alloy consisted of fine primary and eutectic Si phases, evenly distributed in the equiaxed α-Al matrix, whereas the Cu-based SF ternary alloy consisted of uniformly distributed fine eutectic Si particulates and spherical-shaped θ-Al2Cu precipitates, uniformly distributed in α-Al matrix. In contrast, the AC ternary (Al-12.6Si-2Cu) alloy consisted of unevenly dispersed eutectic Si needles and the coarse intermetallic compound θ-Al2Cu in the α-Al matrix. The addition of Cu enhanced the micro hardness of the SF ternary alloy by 8, 34, and 41% compared to that of the SF binary, AC ternary, and binary alloys, respectively. The wear test was conducted using a pin-on-disc wear testing machine at different loads (10–40 N) and sliding velocities (1–3 ms−1). The wear tests revealed that SF alloys exhibited an improved wear behavior in the entire applied load and sliding velocity range in comparison to that of the AC alloys. At a load of 40 N and a sliding velocity of 1 ms−1, the wear rate of the SF2 alloy is 62, 47, and 23% lower than that of the AC1, AC2, and SF1 alloys, respectively. Similarly, at a sliding velocity of 3 ms−1, the wear rate of the SF2 alloy is 52%, 42%, and 21% lower than that of the AC1, AC2, and SF1 alloys, respectively. The low wear rate in the SF2 alloy was due to the microstructural modification during spray forming, the precipitation of fine Al2Cu intermetallic compounds, and increased solid solubility. The SF alloys show an increased transition from oxidative to abrasive wear, while the AC alloys demonstrate wear mechanisms that change from oxidative to abrasive, including delamination, with an increase in sliding velocity and load.