Applied Mechanics and Materials Vols. 813-814

Abstract: The need for super-plasticity and high strength leads to the development of Severe Plastic Deformation technique. The strength of the material is directly dependent upon the grain size of the material. So, there is a need for producing Ultra-Fine Grain microstructure (UFG). UFG material is the material with very small grain size in the range of sub-micrometre. Application of severe plastic deformation, imparts extremely high strain. Equal channel angular pressing (ECAP) is a severe plastic deformation process in which the metal specimen is pressed through an angular channel of equal cross section. The material is subjected to shear deformation and strain is imparted in the specimen. Geometric parameters such as channel angle and corner angle play a major role in grain refinement. Aluminium (Al) specimens are subjected to undergo severe plastic deformation. Since, the strength of Al is not high, other materials are added in order to enhance its mechanical properties by matrix work hardening. Copper (Cu) along with Al shows increase in its strength and also in hardness. An attempt is made with Aluminium and copper, blended in the ratio 95:5 by weight with the main objective to study the Tensile strength, Hardness and Percentage Elongation properties of the specimen.

Abstract: Shape-memory material is an alloy that “Remembers” its original shape and that when deformed to its Pre-deformed shape when heated. Phase transformation temperature is one of the most important parameters for the shape memory alloys. In this present work phase transformation temperature is measured by the dead weight method and compared with standard Differential scanning calorimetry (DSC) method. The objective of this paper is to study the microstructure of the Shape memory alloy (SMA) wire, determining the Phase Transformation temperature of NiTinol alloy i.e. Marteniste start (M_s), Martensite finish (M_f), Austenite Start (A_s), Austenite finish (A_f) by a Dead Weight method and also studying the stress-strain behavior with variation of Temperatures to show the Shape memory effect in the NiTinol SMA wire.

Abstract: Abstract. This article described about the effect of surface modification on newly identified natural fiber in the name of veldt grape stem fibers (cissus quadrangularis) were extracted and investicated. The extracted veldt grape stem fibers (VSF) is treated with alkali chemical with various concentrations like 5%, 10 % and 15 % for a constant soaking time of 60 min. The true cross sectional areas were measured for treated and untreated fibers using electron microscope and image J software. The tensile properties of chemically treated fiber were studied using Instron universal testing machine and found the better tensile properties on 10% chemical concentrations, which considered as optimum case of alkali treatment. The fibers density, chemical compositions like cellulose, lignin, wax, moisture and ash content also studied for optimal case based on tensile strength. The characterization of optimally NaOH treated fibers was analysed by using of XRD technique.

Abstract: The aim of the paper is to study friction force behavior by experimental investigation in the sliding of Inconel 600 alloy. The Inconel alloys are high-temperature Ni-Based alloy which have various applications like gas turbines, heat exchangers, condensers etc. The sliding tests are performed on a pin-on-disc tribometer. The Design of experiments technique is used to find out the number of experiments by using Taguchi’s L27 orthogonal array which is developed in MINTAB 14 software. The experiments were reduced for the various combinations to get the optimal parameters. The results showed that the friction force increases with the increase of load and speed. Also it is found that the speed was most significant parameter affecting frictional force. The regression model helps us to model the values for the responses.

Abstract: This study presents the details of experimental and analytical investigations on three different types of composites on their progress to failure under varied type of loadings. The composites are glass/epoxy-GFRP, Kevlar/epoxy-KFRP and Carbon/epoxy-CFRP composites. A series of experiments were carried out to find the variation in mechanical properties in all composites due to displacement controlled tests with different displacement rates such as 0.5mm/min, 1.0 mm/min and 1.5mm/min. The experimental results for CFRP, GFRP and KFRP under three different zones of response viz., stage I- response upto design load-DL, stage II-later from design load to ultimate load-UL followed by Stage II-response upto failure load-FL were discussed. Comparisons of relative performance under different rates and types of damage occurred are discussed from strength, stiffness and energy points of view.

Abstract: An investigation on the impact of aging on the hardness and wear properties of the Al-Mg-Si alloy with Ni addition was carried out. Al base alloy was melted in an electric furnace and 10wt%Ni was added to the melt. The melt was cast in a metal mould. The cast specimens were solutionized and aged at various temperatures. The microstructure was observed using an optical microscope. The hardness, wear rate and CoF were determined. The eutectic Si morphology was refined. An optimum aging temperature (165 °C) was found to exist for the Ni-modified alloy. The hardness increased (by 4.5%), wear rate decreased (by 96%) and CoF remained at a constant value for the Ni modified alloy compared to the base alloy. It is concluded that the Ni addition significantly improves the properties of the base alloy.

Abstract: Abstract. In recent years, Aluminium alloy based metal matrix composites (MMC) are gaining wide spread acceptance in several aerospace and automobile applications. These composites possess excellent wear resistance in addition to other superior mechanical properties such as strength, modulus and hardness when compared with conventional alloys. The hybrid composites are new generation of composites containing more than one type, shape or sizes of reinforcements giving superior combined properties of reinforcements and the matrix. In the present work, Al6061 has been used as matrix material and the reinforcing materials selected were SiC and Graphite particulates of 10 to 30µm size. Composites Al6061-Gr (2- 8 wt. %), Al6061-SiC (2 -10wt. %) and Hybrid composites with Al6061 matrix alloy containing 3wt% graphite and varying composition of 2-10wt% SiCp were prepared by stir casting technique. The cast matrix alloy and its composites have been subjected to solutionizing treatment at a temperature of 530 ± 20C for 6 hours, followed by ageing at a temperature of 175 ± 20C for 6 hours. The mechanical properties of as cast and T6 heat treated composites have been evaluated as per ASTM standards and compared. Addition of Graphite particulates into the Al6061 matrix improved the strength and ductility of the composites. Significant improvement in tensile strength and hardness was noticed as the wt. % of SiCp increases in Al6061-SiC composites. Addition of Graphite into Al6061-SiC further improved the strength and ductility of hybrid composites. The heat treatment process had the profound effect in improving the mechanical properties of the studied composites. The microstructural studies revealed the uniform distribution of SiC and Gr particles in the matrix system.

Abstract: In this paper, 6 mm thickness dissimilar aluminium alloys of 5083 (H321) and 2219 (O) butt joints were fabricated successfully by friction stir welding process. The quality joints were obtained for the welding parameters of 35 mm/min and 650 rpm with the shoulder diameter to pin diameter ratio as 3. Macrostructure study shows that the interface between the weld nugget and TMAZ is smooth and clear with a flow arm extending towards the top surface of the weld in the 2219 side. The boundary on the 5083 side between the weld nugget and the TMAZ was irregular. The obtained joint efficiency is around 92.57% based on the UTS of the softer material (AA2219). The tensile test results showed that the specimens failed in the heat affected zone of the softer base material 2219. The hardness values in the stirred zone are higher than the softer base material of alloy 2219. The friction stir welded dissimilar joint 2219-5083 exhibited better general corrosion characteristics than the 2219-2219 weld and 2219 base material.

Abstract: The Synthesis of aluminium matrix composites is receiving considerable emphasis in meeting the requirements of various industries. Due to the desired properties such as low weight, high specific strength, good corrosion resistance and excellent wear resistance, they have received a great interest in the recent years. Metal-matrix composites (MMCs) based on aluminium and magnesium has emerged as an important class of materials and Al₂O₃ can be considered as ideal reinforcements, due to their high strength, high aspect ratio and thermo-mechanical properties. The objective of this work is to reinforce Al 1100-Mg alloy with different wt% of Al₂O₃ (0, 3, 6, 9 and 12) was added by melt stirring method and Extrusion is carried out (extrusion ratio of 12.25) for the same alloy and composites. Mechanical property like hardness and tensile properties have been investigated for cast and extruded of base alloy and composites.

Abstract: Copper based shape memory alloys are the alloys prepared with the combination of 66-88 wt% of copper, 10-14 wt% of aluminum, 0.3-0.6 wt% of beryllium and 0.1-0.4 wt% of manganese in the induction furnace through ingot metallurgy. The prepared SMAs is subjected to homogenization, it was observed that the samples exhibits Beta phase at high temperature and shape memory effect after going through step quenching to a low temperature. Microstructure and Shape memory effect was studied with the help of optical microscope and bend test respectively. It was seen that with increase in wt % of manganese the shape memory effect also increases.