Materials Science Forum Vol. 969

Abstract: In the present experimental study, the effect of turning tool overhang on the chip morphology and vibrations during orthogonal turning has been investigated. Orthogonal cutting (turning) setup was developed to ensure the cutting process happens in a 2-dimesional plane. Orthogonal cutting was realized by turning a circular tube with geometry of 33.88 mm external diameter and 3.5 mm wall thickness (7075-T6 Alloy). High speed steel (HSS) rod with a square cross-section (1⁄2 x 1⁄2 square inch) was used to fabricate the orthogonal turning tool with a geometry of 15 ̊ back rake angle and 9 ̊ clearance angle. The cutting experiments were conducted for different tool overhang lengths (2cm, 3cm, 4cm, 5cm & 6cm) by keeping constant cutting speed (25 m/min) and feed (0.15mm/rev). The vibrational characteristics were measured using accelerometer and Ni-DAQ card. The morphology and microstructure of the chips collected during cutting were studied under optical microscope using metallographic procedures. It was found that for increasing overhang length of cutting tool the chips serrations was found increasing. The frequency of cutting tool and amplitude of vibration was found increasing with increasing tool overhang length.

Abstract: AISI 1050 Alloy has a Wide Range of Applications and were Subjected to Machining Operations. the Purpose of the Study is to Find the Optimum Input Plain Turning Process Parameters at Three Levels, Using L18 Orthogonal Array and Grey Relation Analysis; and to Investigate the Mechanical and Microscopic Properties of the AISI 1050 Alloy before (untreated, UT) and after Annealing (AN) (heat-Treatment, HT) Process. the Results of Conducted Experiments Revealed the Optimum Process Parameters as Following for the Untreated Specimens: Spindle Speed at 3500 r.p.m., Feed 0.08 Mm/rev, Depth of Cut at 0.6 Mm, Insert Corner Radius at 4mm, and Cutting Fluid Concentration at 12 %, are the most Optimum Conditions to Obtain Minimum Power Consumption for the Untreated Specimens. whereas, a Spindle Speed at 3500 r.p.m., Feed at 0.08 Mm/rev, Depth of Cut at 0.6mm, Insert Corner Radius at 4 Mm, and Cutting Fluid Concentration at 12 % are the Optimum Parameter Values for the Treated Specimens.

Abstract: Fabrication of nanocomposites is a highly challenging task because of the particles need to be disseminated across the molten liquid due to broad surface area, poor wettability. Homogeneous dispersion is tough in traditional stirring methods leads to cluster and agglomeration formation in high viscous molten metals. In such attempts, the ultrasonic vibration process exhibits the better dispersion and distribution of nanocomposites with enhanced material properties as compared to other fabrication processes. This paper deals with the fabrication process, probe design and effective process parameters of sonication process to the uniform dispersion of nanoparticles.

Abstract: This paper presents the recent studies on the fabrication of magnesium based metal matrix nanocomposites (MMMC) by using ultrasonic assisted stir casting technique. The pure metal and alloys, due to their limited mechanical properties are not suitable for various engineering applications. It has been observed that the addition of suitable reinforcements into metallic matrix improves the specific strength, ultimate tensile strength, porosity and wear properties as compared to the conventional and monolithic engineering materials for aerospace and automotive applications. The effects of ultrasonic vibrations and the resulting uniform dispersion of reinforcements on the mechanical and tribological properties of magnesium based MMCs are specifically highlighted in this paper.

Abstract: In the present study, TC4 titanium alloy was gas tungsten arc welded to evaluate the mechanical and metallurgical properties of the welds. The welds were carried out at different welding conditions such as welding speed and current to identify their effect on microstructural changes and strength of the welds. The results of bead geometry measurements suggests that the fusion zone width and depth was greatly varying with the welding speed and current. It is also observed that the fusion zone microstructure and heat affected zones are greatly controlled by welding conditions. Therefore the mechanical properties of the welds were improved with the changes in welding conditions and are correlated with the metallurgical features of the welds. The optimal welding conditions were analysed using Box-Behnken design and analysis of variance technique for identifying strength of the welds and better bead geometry parameters.

Abstract: Among several existing and well established severe plastic deformation techniques, constrained groove pressing (CGP) is one of the prominent and trusted routes for producing ultrafine grained materials. In the present work medical grade 316L austenitic stainless steel sheet of 3 mm thickness was subjected to CGP up to two cycles. Samples obtained as a result of processing were investigated both experimentally and numerically through finite element (FE) analysis using DEFORM-3D software. XRD study revealed the transformation of austenitic phase to martensitic phase. Tensile and hardness tests were conducted to see the effect of processing on mechcanical properties. The ultimate tensile strength increases with the number of CGP passes from 767 (solution annealed) to 1162 MPa (after 2 cycles), similarly, yield strength increases from 269 (as received) to 328 MPa (after 2 cycles). Finite element analysis showed an imposed strain of 2.30 with standard deviation of 0.31 after two cycle of CGP is in coordination with experimental measured strain of 2.32.