Applied Mechanics and Materials Vols. 592-594

Abstract: Cu-Al-Be ternary alloy was prepared by ingot metallurgy route. Cu-Al-Be SMAs exhibit good shape memory properties. With the addition of Cr as quaternary alloying element to the ternary Cu-Al-Be alloys, their shape memory properties have been improved. The ternary alloy was added with 0.1, 0.2, 0.3 and 0.4wt. % Cr. The influence of the quaternary alloy was analyzed by Optical microscope, Hardness, Strain recovery and transformation temperature. With increase in Cr content, good grain refinement and less hardness have been observed. Good strain recovery was found in 0.2 % wt. Cr added alloy.

Abstract: A hybrid Al7075 metal matrix composites have been fabricated through liquid metallurgy route (Stir Casting method) using Al₂O₃ and B₄C as reinforcement materials. The effect of weight percentage of reinforcement materials on mechanical properties of the composites have been studied by varying the weight percentage of Al₂O₃ as 3, 6, 9, 12 and 15% while keeping constant weight percentage of B₄C (3%). The as-cast microstructure, tensile strength, micro and macro hardness of the fabricated hybrid composites have been studied. The mechanical properties of the prepared composites were increased with increasing the weight percentage of the reinforcement in the composite. The maximum tensile strength, micro-hardness and macro-hardness of 309 MPa, 140 VHN, and 112 BHN, respectively, were obtained for a hybrid Al7075 matrix composite containing 15% Al₂O₃ and 3% B₄C.

Abstract: Influence of ageing temperatures and ageing time intervals on the intermetallic phases of high Mo superaustenitic stainless steel (SASS) is studied. To form the intermetallic phases the alloy was aged for 1 hour and 10 hours at different temperatures in the range of 500-1000°C. Chi forms at temperatures up to 800°C. Sigma forms above 900 or 1000°C depending upon the ageing time. A property diagram is simulated using Thermo-calc software to corroborate the formation of chi and sigma phases as a function of ageing temperatures. EDS of sigma indicated its higher Mo content compared to the chi phase. Chi is enriched in chromium while sigma is enriched in Mo.

Abstract: This study focuses on the effect of cutting parameters on the tool wear in a CNC end milling operation. Major factors which influence the tool wear are spindle speed, feed rate and depth of cut. Conventionally constant feed rate is used. In this work a concept of progressive feed rate is introduced. AISI 1045 steel has been chosen as it is widely used in manufacturing. Design of Experiments (DOE) technique was adopted to conduct the experiments. Experiments were conducted for both the existing and the proposed feed rate method and the tool wear was compared. A statistical model was developed using Design Expert software. The predicted values were compared with the experimental values and were found to be in close agreement. The model adequacy was checked using ANOVA technique.

Abstract: Recent concerns over the environment, increasing fuel prices and scarcity of its supply have promoted the interest in development of the alternative sources for petroleum fuels. This paper deals with the production of methyl esters from Simarouba Glauca oil and Mahua oil by transesterification process using potassium hydroxide as a homogeneous catalyst, calcium oxide as a heterogeneous catalyst and methanol as the alcohol. The important properties of Methyl esters such as cloud point, pour point, ash content and carbon residue are tested and compared with other biodiesels. Methyl esters are blended with diesel in different proportions and testing the physicochemical properties such as viscosity, flash point, density and copper corrosion for each blended biodiesel.

Abstract: Multi-Criteria Decision Making (MCDM) method plays a key role to find out the best option from all possible alternatives. From different application areas Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) is one of the Multi-Criteria Decision Making (MCDM) method to find out the correct result. TOPSIS is a real-world and valuable procedure for ranking and selection of a number of externally determined substitutes through distance measures. In this paper, application of techniques for order preference by similarity of an ideal solution (TOPSIS) method is applied for solving multiple criteria (objective) optimization problem in mechanical and physical properties of jute/Al₂O₃ fiber based hybrid composites. The best performance value of composite is designed from ideal solution and as well as the worst performance value of composite is designed for negative-ideal solution. The results have demonstrated the model to be both robust and efficient.

Abstract: Slurry erosion is a major concern in marine components which are subjected to wear and corrosion. These problems are addressed by developing materials which are harder and possessing excellent corrosion resistance in sea water. In this regard, there are serious attempts to modify the existing surfaces or developing new composite materials which are hard and also possess good strength. There are few reports suggesting the improved slurry erosion resistance of aluminium alloy by dispersing SiC within the metallic matrix. Higher the extent of SiC in the matrix material, better will be the slurry erosion resistant. In the light of above, the present work will focus on innovative development of Al6061-SiC composites by the combined process of powder metallurgy and casting followed by hot extrusion. A maximum amount of 40 wt % of SiC has been successfully incorporated in the hot extruded composites. The hot extruded composites are subjected to slurry erosive wear test in 3.5% NaCl solution containing silica sand particles. The parameters such as slurry concentration, rotational speed used in the present study are 10-30g/l, 500 – 1000 rpm respectively with test duration maintained at 24 hr. It is observed that increased content of SiC in matrix alloy has resulted in significant improvement in the slurry erosion resistance of the developed composites.

Abstract: Small punch creep (SPC) testing technique is a material non-intensive testing technique for evaluating creep behavior of materials using miniature specimens. It can be used for remnant life assessment (RLA) studies on components in service, by scooping out limited material for testing without impairing the strength of component. In order to ensure the reliability of use of SPC technique for RLA, it is necessary to establish sound database on SPC properties of the material before putting into service. In this investigation, SPC technique was used to evaluate creep properties of 316LN stainless steel using specimens of size 10 x 10 x 0.5 mm. SPC tests were conducted in load controlled mode at 923 K and at various loads. SPC curves clearly exhibited primary, secondary and tertiary creep stages. The minimum deflection rate increased and rupture life decreased with an increase in applied load. Like in conventional creep test results, the minimum deflection rate obeyed Norton’s power law and Monkman-Grant relationship. SPC test was correlated with corresponding conventional creep test. Good correlation was established between creep rupture life values evaluated from SPC tests and conventional creep tests.

Abstract: Aluminum boron carbide metal matrix composites (Al-MMC) have got wide applications in aeronautical and automobile industries due to their excellent mechanical and physical properties. Due to the presence of harder reinforcement particles, machining of these composites is a difficult task. The results of experimental investigation on mechanical and machinability properties of Boron carbide particle (B₄C_p) reinforced aluminum metal matrix composites are presented in this paper.The influence of reinforced ratio of 7 wt% of B₄C_p on mechanical properties was examined. It was observed that addition of B₄C_p reinforcement resulted in improvement in hardness and tensile strengths to the extent of 71% and 38.4% respectively. Fabricated samples were turned on medium duty lathe of 3 kW spidle power with Poly crystalline diamond tool (PCD) of 10 μm particle size at various cutting conditions. The effect of machining parameters, e.g. cutting speed, feed rate and depth of cut on cutting forces and formation of BUE was studied.

Abstract: The expectations over novel composite materials have been increased especially in automotive and aerospace applications due to its superior weight to strength ratio and tailored mechanical properties. In this frame work, aluminum alloy AA5083 alloy matrix reinforced with micron (10% wt – 5% wt) and nanoparticles (1% wt – 5% wt) of Al₂O_3. The composite samples were fabricated through powder metallurgy route. Optimum amount of reinforcement were determined by evaluating mechanical properties like micro-hardness and compressive strength of composites. The characterizations were probed by Scanning Electron Microscope (SEM) and X-ray Diffraction (XRD) methods. The results reveal that the composites containing 2% wt of nanoAl₂O₃ and 8 % micro Al₂O₃ reinforcement witnessed superior mechanical properties due to its combined effect of concentration and particulate scale and the great isotropic behavior was achieved by homogenous dispersion of reinforcement in the matrix phase.