Sandwich composite of aluminum alloy and magnesium alloy through accumulative roll bonding technique

Aluminum and magnesium alloys are lightweight materials with outstanding technical uses. Due to their combined qualities, composites built of aluminum and magnesium alloys have surpassed the utilization of these elements individually. Accumulative Roll Bonding was used to create a three-layered sandwich composite structure made of Al-alloy/Mg-alloy/Al-alloy. The composite structure's microstructure and mechanical characteristics were studied. A fine-grained AZ31 layer was formed, according to the microstructural study. At the Al-alloy/Mg-alloy contact, a diffusion layer was also seen. On the broken surface, fractography exhibited both ductile and brittle failure characteristics

Development and tribological characterization of fly ash reinforced iron based functionally gradient friction materials

The tribological and thermal properties enable iron based sintered materials with hard phase ceramic reinforcements as promising friction material for heavy-duty wind turbines. In wind turbines, the braking system consists of aerodynamic and mechanical braking systems. During application of mechanical brakes, the friction materials are pressed against the rotating low-speed shaft. The desired braking efficiency is achieved by utilizing a number of friction materials, which in turn are joined in a steel backing plate. Though this arrangement increases the braking efficiency, the hard phase ceramic reinforcement particles reduces the bonding strength between the friction material and steel backing plate. The joint failure leads to catastrophic failure of wind turbine. Therefore, the need of the hour is to develop friction materials with functional gradients that have high wear resistance (contact area) and high bond strength (interface). In this study, an attempt is made to fabricate and characterize a friction material with gradient profile of composition along the cross section to provide functional gradient property. The functional gradient friction material is synthesized by gradient deposition of Fe, Cu, Cg, SiC and fly ash powders which is then compacted and sintered. The prepared functional gradient friction material was characterized in terms of microstructure and microhardness. The tribological performance (wear rate and coefficient of friction) of the developed functionally gradient friction material was investigated at various loads using pin-on disc apparatus. The results show that as the load increases, the wear rate decreases and at the same time the COF tends to increase at higher loads. The predominant wear mechanism was deduced from the morphology of the worn surface

Tribological Performance of the Continuous Steel Fiber-reinforced Cu based Friction Material for Heavy-duty Braking Applications

Brake pads are the major components of the wind turbine, which primarily consists of metal matrix and ceramic reinforcements. The ceramic particles plunge out during the application of brakes, which in turn leads to the transformation of the wear mechanism from adhesive to abrasive wear. This increases the wear rate and therefore the study investigates the possible replacement of ceramic reinforcements with continuous fibers that exhibit high strength and compatibility. In recent years, Cu-based brake pads that are fabricated by powder metallurgy route are widely used in wind turbines. In this study, continuous fibers of stainless steel SS304 are reinforced in the Cu matrix by the casting method to preserve the fiber alignment. The fabricated composite is characterized for microstructure, microhardness, and tribological behavior. Besides, a comprehensive analysis of the wear mechanism in the developed composite is presented based on the surface morphology, elemental composition, and phase analysis

Corrosion and Tribological Characteristics of FSPed Aluminum Alloy AA5052

Friction stir processing (FSP) is a solid-state and effective process for surface modification of aluminium alloys. In this study the AA5052 alloy, widely used in marine applications, has been subjected to FSP. The FSP trials have been carried out by altering the FSP process parameters (tool rotation speed, tool traverse speed, and shoulder diameter). The friction stir processed specimens have been characterised / tested for microstructure, microhardness, sliding wear, immersion corrosion, and electrochemical corrosion. The hybrid polynomial – radial basis function-based models have been developed to determine the relationship between the process parameters and the evaluated properties. Furthermore, the optimum parameters for obtaining high hardness, wear resistance, and corrosion resistance have been determined. Microstructure evaluation in the friction stir processed specimens has shown refinement and uniform dispersion of β particles throughout the α-Al matrix. The results show that the improvement in properties is a result of the homogeneous dispersion of secondary β phase particles in the matrix. Friction stir processing of AA5052 alloy has improved hardness by ~14.5%, wear resistance by ~83%, and corrosion resistance ~87%. The optimum process window for friction stir processing of AA5052 alloy is tool rotation speed between 500 rpm and 900 rpm, tool traverse speed between 10 mm/min and 30 mm/min, and tool shoulder diameter of 18 mm and 21 mm

Development and Tribological Characterization of Semi-Metallic Brake pads for Automotive Applications

Semi-metallic brake pads are quite a good choice for performance-driven automotive industries, because of improved braking performance in a more comprehensive range of temperatures. In this study, a semi-metallic brake pad is fabricated through a powder metallurgy processing technique with two compositions of powders with a different weight ratio of Copper (Cu), Iron (Fe), flash, Aluminum oxide (Al2O3), Barium sulfate (BaSO4), Phenolic resin, Low-Density Polyethylene (LDPE), Graphite for automotive application. A well-distributed composition was indicated by the microstructure, which exhibited a uniform dispersion of hard particles throughout the matrix. BP-20Cu-20Fe specimen exhibited a high hardness value of 171Hv. Under higher loads of 70 N, the specimen BP-20Cu-20Fe showed excellent wear resistance, with a low wear rate of 1.072×10-6 g/Nm. On the other hand, specimen BP-20Cu-20Fe showed a notable 35% increase in friction coefficient when the load was increased from 30 N to 70 N.The surface morphology, elemental distribution, and worn surface features and characteristics are examined using advanced instrumental techniques

Influence of Friction Stir Processing Parameters on the Mechanical and Corrosion Properties of Al-Cu-Li Alloy

Novelty: Most of the open literature research has focused on the microstructural evolution and mechanical properties of AA2050 alloy. Also, a significant study discusses the corrosion behavior of AA2050 alloy based on immersion and electrochemical characteristics. The influence of heat treatment on the microstructure and mechanical properties of friction stir processed AA2050 alloy is scarcely discussed in the open literature. The hot salt corrosion characteristics of friction stir processed AA2050 seldom exists in the available literature. This study concentrates on microhardness, tensile strength, and corrosion properties of friction stir processed AA2050. Also, the work focuses on the influence of artificial aging on the microhardness, and tensile strength of the friction stir processed AA2050