Key Engineering Materials Vol. 982

Abstract: A porous nickel (Ni) was brazed to copper (Cu) and stainless steel 304 (SS304) using VZ2250 and MBF67 brazing filler metal with a composition of 77.4Cu-9.3Sn-7.0Ni-6.3P and 64.5Ni-25Cr-6P-1.5Si (Cu: Copper, Sn: Tin, Ni: Nickel, P: Phosphorus, Cr: Chromium, Si: Silicon), respectively for joint microstructure and mechanical properties analysis. Porous Ni with a pore density of 15 pores per inch (PPI) was sandwiched between Cu/VZ2250 and MBF67/SS304. A brazed joint of Cu/Porous Ni/SS304 with VZ2250 and MBF67 brazing filler metal was prepared in a high vacuum furnace at different brazing times of 5, 10, and 15 minutes for 1015 °C with a heating and cooling rate of 10 °C/min, respectively for comparison purpose. The microstructure and mechanical properties of the brazed joint were investigated to identify the joint ability after the brazing process. Scanning Electron Microscope (SEM) equipped with Energy Dispersive X-Ray Spectroscopy (EDS) confirmed the interfacial microstructure by the formation of the diffusion filler metal (dark grey colour) for the Cu/Porous Ni/SS304 with VZ2250 and MBF67 brazing filler metal. For shear strength tests, the value decreases with an increase in the brazing time. The shear strength tests for the brazed joint of Cu/Porous Ni/SS304 with VZ2250 and MBF67 brazing filler metal show the maximum shear strength test value can be achieved for the brazing time of 5 minutes. The decreasing shear strength value was observed with differences in structural data of porous Ni due to the softening after the brazing process. Keywords: Brazing, Microstructure, Porous Nickel, Shear Strength.

Abstract: This research is a finite element simulation on resistance spot welding (RSW) process between dissimilar sheet metals consist of Titanium alloy, Ti-6Al-4V and Austenitic Stainless Steel (ASS) 316L. The problem statement was inability to visualize the stress concentration profile over weld nugget joint when Titanium alloy and steel welded with variable electrode geometry of circle, triangle, square and hexagon. To determine the best geometry for best weld with lowest maximum stress concentration. The methodology of simulation was tensile-shear test using SOLIDWORKS software. The tensile-stress load of 664.09 N was applied across all 4 different weld geometries. The result for the lowest magnitude of maximum stress 180.6 MPa was on circle weld geometry. Triangle geometry registered highest stress concentration of 219.6 MPa. This proves that most common weld geometry used in industry was circle. Even for dissimilar material joint the result supports that circle weld geometry as the best geometry. Keywords: Resistance spot welding (RSW), stress concentration, weld nugget, weld geometry.

Abstract: The current study proposes to investigate the thermal, wettability and mechanical properties of a low temperature SnBi solder. The main aim is to investigate the performance of the SnBi solder alloy with different Bi composition. The study also establishes the relationship between melting temperature, spreading area and tensile stress of the SnBi with different Bi composition at different low reflow temperatures. The thermal and wettability tests are conducted experimentally, while the mechanical test will be analysed via finite element analyses (FEA). The single shear lap test method was adopted for the simulation. The thermal properties of the SnBi solder are investigated using the differential scanning calorimeter (DSC). The reflow temperature selected ranges from 160 °C to 220 °C to accommodate the purpose of low temperature soldering. Wetting test results showed that spreading area of Sn48Bi solder alloy increased to 28.1 and 42.88 at 180 °C and 210 °C respectively. The increase in the Bi composition reduced the tensile strength regardless of the increase of the reflow temperature. The preliminary results commend the characteristics of the SnBi solder as a possible alternative to the Pb solder.

Abstract: This study analyse the effects of different wire drawing experimental tests on the die and product properties. Drawing load, temperature, and wear rate are main die factors, that concerned with the interaction effects of drawing speed variation, wire angle alignment and lubrication. For the product, two factors; tensile strength and hardness are taken. A copper wire is drawing from (4.3 mm) into (3.5 mm) diameter with an area reduction of 1.65, 34% ratio.Six dies were employed in various alignments at three different angles (0°, 1°, and 2°), each has two different drawing speeds of (20 mm/min and 40 mm/min). Results show, the highest drawing load and temperature values in die no.5. The effect of using grease on the die wear rate found that the die wear decreases compared to without. But, when using mixed gradients under the same working conditions, the wear rate changed into coating layer on the die surface. The interaction effect of wire alignment on the product strength showing very small when dealing with low or higher speed, but elongation and ductility are significantly reduced with increasing the angle. The wire produced from die no.1, gives the highest micro hardness.

Abstract: A modification cutting tool is a type of cutting tool that can be altered or adjusted to change its cutting properties. This can include changing the angle or shape of the cutting edge, adjusting the depth of cut, or modifying the material or coating used on the tool. These modifications allow for greater precision and efficiency in cutting operations, particularly in industries for manufacturing and construction different products. Ceramic materials can be used in coatings to provide a variety of benefits, such as corrosion, wear resistance , and thermal insulation. They also offer high hardness, low friction, and chemical stability. Ceramic coatings can be applied to various substrates including metals and ceramic. Modification of cutting tools using nanomaterial deposition is a promising approach to enhance their performance and durability. The process involves depositing one or more layer of nanosized particles onto the surface of the cutting tool, which can improve its mechanical, thermal, and tribological properties. Keywords: Ceramic materials ; coating ;cutting tools; coating process.

Abstract: In the present study, the production of aluminum foam was carried out using the powder metallurgy technique, specifically employing the sintering – dissolution process (SDP). The SDP method, which constitutes a sequential series of four well-defined steps, was employed to achieve the desired foam structure and properties. These steps involved carefully controlling the parameters and conditions throughout the process to ensure successful foam formation. Aluminum powder with a particle size of (1.99 μm) as a raw material was mixed with NaCl with a particle size between (150-425μm) used as a space holder at different ratio (25, 35, 45and 55 wt. %.). Obtained Al-foam with 45% NaCl demonstrated the most optimal structure. Some additives (Mg) added to the powder mixture, it was found that the mechanical and the tribological properties of the produced foam were improved. The introduction of metal’s micro-particles led to a notable enhancement in both compressive stress and micro-hardness, the compressive stress increased substantially from 15.2 MPa to 56.5 MPa for the foam containing 45% NaCl and 45% NaCl + Add., respectively. While the micro-hardness exhibited a noteworthy increase from 51.5 HV to 62.1 HV. Results also showed important reduction in the wear rate from (0.00000155 g/cm) to (0.00000079 g/cm) for the Al-samples of (45% NaCl) and (45% NaCl+ Additive) respectively, the lowest value recorded for the coefficient of friction was (0.15) for (Al-Foam with 45% NaCl + Additive) compare to (0.19) and (0.21) for (Al-foam with 45% NaCl) and (pure Al) respectively at 10 N applied load and 800 rpm.