S. Narendranath

Abrasive Wear Behavior of Granite-Filled Glass-Epoxy Composites by SiC Particles Using Statistical Analysis

This experimental investigation deals with the evaluation of abrasive wear behavior of Glass Epoxy (G-E) composites on pin-on-disc test rig. A plan of experiments, based on the Taguchi Design of Experiments, was performed to acquire data in controlled way. An orthogonal array and the analysis of variance were employed to investigate the percentage of contribution of various process parameters like sliding speed, applied load, sliding distance and their interactions affecting the abrasive wear volume loss of composites. The correlations between the various factors affecting the abrasive wear behavior of composites were obtained by using multiple linear regression equations. The obtained results indicate that applied load and sliding distance were the wear factors that have the highest physical as well as statistical influence on the abrasive wear behavior of both filled and unfilled G-E composites. A good agreement between the predicted and actual wear resistance was observed within ± 12%.

Effects of 4.5% Copper Addition and Melt Treatment on Microstructure and Wear Properties of Al-7Si Alloy

The present study describes the effects of addition of 4.5 wt% of copper on microstructure and wear properties of cast Al-7Si base alloy. Grain refiner (1 wt% of Al-1Ti-3B) and grain modifier (0.2 wt% of Al-10Sr) were added together to Al-7Si base alloy and Al-7Si-4.5Cu alloy and effect of alloy composition, microstructure and normal pressure on wear properties were studied. Results indicated that combined grain refined and modified Al-7Si-4.5Cu alloys had uniformly distributed α-Al grains, eutectic Al-Si and fine CuAl2 particles in the inter dendritic region. In both alloys (Al-7Si and Al-7Si-4.5Cu) the wear properties improved after combined melt treatment. The addition of 4.5% copper resulted in improved wear characteristics as compared to both untreated and treated Al-7Si alloys. SEM / EDS analysis were carried out on cast alloys and worn surfaces.

Development and Characterization of Al-Si-Cu FGM Using Centrifuge Technique

In this work Al-Si-Cu Functionally Graded Material (FGM) is developed using centrifuge technique. The method used in this work to produce FGM is totally different compared to other centrifugal process which helped in producing solid cylindrical parts. The FGM is characterized through Microstructure and Hardness and it is found that the Cu segregated at the bottom of the casting and Si at the top due to the density difference. Similarly the hardness and the ultimate tensile strength at the bottom of the casting and at the top of the casting region is more when compared to region in-between the top and bottom of the casting.

Effect of Process Parameters on Centrifugally Cast Al-Si FGM

Functionally Graded Materials (FGM) are such kind of materials wherein the properties and structure are varied from one end of the cast to the other intentionally. Centrifuge technique has been used in this study to produce Al-Si FGMs. Several process parameters determine the microstructure and the distribution of phases in the FG casting. These parameters include the size and initial concentration of alloying element, the centrifugal force, solidification rate, cooling rate. In this work an attempt has been made to produce FGMs using three different process variables such as mold temperature, melt temperature and mold rotational speed, their effect on the structure and properties. For this study Al-17wt%Si is used. From the results it is seen that for a particular melt and mold temperatures by increasing the mold rotation speed enhances the segregation of the Si particles at the one end of the casting. Similarly increasing mold or melt temperature only, increases the segregation.

Collapse Mechanism of Foam Cored Sandwich Structures Under Compressive Load

In this work the moisture absorption capability, compressive properties, collapse modes of various types of composite sandwich structures are reported. The tested sandwich structures were constructed with varieties of hybridized skin materials and different compositions of the core materials. The moisture absorption, Flatwise compression and Edgewise compression tests are conducted for core as well as sandwich structures. Comparisons of results have been between the hybridized and non-hybridized sandwich structures. Two modes of collapse were noticed in the Edgewise compressive test, one of which being progressive end-crushing of the sandwich structure featured by significant crash energy absorption. This feature was highly desired for the parts of transportation vehicles. Microscopic analysis has been carried out to know the nature of failure under compressive loads. It has been observed that with increasing the debonding strength of the core–face interface, the failure mode changes from unstable collapse mode stable progressive crushing.