Microstructure Evaluation on Micro and Nano Slag Particles Reinforced AA7075 Composites

The research work was focused on utilization of solid industrial waste. In order to investigate the properties of Fe-Cr slag particulates strengthened AA7075 composites. In this paper addition of ferrochrome slag particles as reinforcement in AA 7075 alloy processed through stir casting technique. By varying size of ferrochrome slag particles were added to evaluate the size effects in the given alloy matrix. Prepared composites were subjected to heat treatment and evaluated for microstructure analysis. The results show that there is a uniform distribution of particles in the matrix and that there is a strong bond between the matrix and the reinforcement. Grain refinement in the alloy matrix is observed by inducing slag particles. Further nanocomposites show lower grain size values.

Influence of Micro and Nano Particles on Mechanical Behaviour of Slag Reinforced AA7075 Composites

Present studies are based on adding ferrochrome slag as reinforcement in AA 7075 alloy manufactured via the stir casting process. Two different slag particles are chosen; they are 36μm (Micro) and 68 nm (Nano). This was added to evaluate the size effects in the given alloy matrix. The composites were tested for unique microstructural properties and mechanical properties. The results Revealed uniform particle distribution within the matrix and good bonding between the matrix and the reinforcement. Better mechanical properties are obtained for both micro and nanocomposites than base alloy. This is further enhanced by ageing treatments. nanocomposites show superior mechanical properties than either alloy or micro composite. Interestingly, nanocomposite exhibits an increase in strength with good ductility; same is confirmed with fracture studies.

PENENTUAN KECEPATAN PEMOTONGAN EFEKTIF BERDASARKAN NILAI KEKASARAN PERMUKAAN MATERIAL AA-7075 PADA PROSES FACE MILLING

During face milling machining, several machining parameters such as feed rate and cuttingspeed determine the surface quality of the workpiece produced by the process. The selection of the rightparameters will lead to the surface quality as planned. Therefore, to improve machining effectiveness, amethod is needed to determine the appropriate machining parameters to produce the desired surfacequality. This research was conducted using a milling machine, five variations of cutting speed and fivevariations of feed rate were used to cut the workpiece aluminum alloy 7075. After machining, the surfaceroughness was measured using a surface test. The surface roughness value is then substituted into thefeed rate equation and effective cutting speed. By finding effective cutting parameters, the machiningprocess will be more efficient and effective without using unnecessary resources. From the results of thestudy note that the development equation to determine the feed rate based on the value of surfaceroughness is ???? = 0,6????√???? ????????0.443mm/tooth. Development equation to determine the effective cutting speedbased on Surface roughness value is ???????? = 3.0686????????0.124 mm/min

Investigation of corrosion behavior on plastically deformed aa 7075 t651 by shot peening process

As AA 7075 T651 comprehensively is used in the marine naval vessels, the factor of corrosion performance always plays a significant role. In this work, an investigation is carried out to study the effect of corrosion behaviour of shot peened AA 7075 T651 in 3.5% solution. From the potentiodynamic polarization study, a 27.72% decrease is ascertained in the Icorr in shot peened specimen in correlation to unpeened aluminium alloy. A drop in Icorr from 1.883 to 1.480 mA/cm2 in shot peened specimen, indicates enhanced pitting corrosion resistance. An electrochemical impedance spectroscopy reveals a surge in the oxide layer formation on the peened surface aiding the drop in corrosion rate. Resistance to pit formations and improvement in oxygen deposition in the peened specimen is observed availing a Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray analysis (EDX). The micro structures of the peened and unpeened specimen are captured using optical microscopy and Transmission electron microscopy (TEM). Micro-strain, dislocation density is also calculated from the X- ray diffraction analysis (XRD), in which grain size reduces by 28.07%, dislocation density surges by 38.65% and micro strain increases by 21.95% in peened specimen in correlation to unpeened AA 7075 T651, resulting in a surge in corrosion resistance by 27.92% in the peened specimen in correlation to unpeened aluminium alloy.

Experimental Investigation of Dry and Cryogenic Friction Stir Welding of AA7075 Aluminium Alloy

An attempt has been made to investigate dry and cryogenic friction stir welding of AA 7075 aluminium alloy, which is predominantly availed in aerospace and defence component industries. These industries avail friction stir welding for joining two nonferrous materials, and minimal deviations and maximum strength are the preliminary and long time goal. A cryogenic friction stir welding setup was developed to conduct the joining of two aluminium alloy pipes. An increase of 0.76–42.93% and 3.79–31.24% in microhardness and tensile strength, respectively, is ascertained in cryogenic friction stir welding in correlation to dry friction stir welding of aluminium alloys. TOPSIS evaluation for the experimental run indicated tool profile stepped type, pipe rotation speed of 1000 rpm, welding speed of 50 mm/min, and axial force of 8 kN as close to unity ideal solution for dry and cryogenic friction stir welding of AA 7075 aluminium alloys. The friction stir-welded component under the cryogenic environment showcased drop in temperature, curtailed surface roughness, and fine grain structure owing to reduction in temperature differential occurring at the weld zone. A curtailment of 50.84% is ascertained in the roughness value for cryogenic friction stir welding in correlation to dry friction stir welding of AA 7075 alloy. A decrement of 21.68% is observed in the grain size in the cryogenic condition with correlation to the dry FSW process, indicating a drop in the coarse structure. With the curtailment of grain size and drop in temperature differential, compressive residual factor and corrosion resistance attenuated by 40.14% and 67.17% in the cryogenic FSW process in correlation to the dry FSW process, respectively.

Tribological Characteristics of Thermomechanically Processed 7075 Al Alloy Through Nano-scratch Characterization

Age-hardenable Al–Zn–Mg–Cu (AA 7075) alloys can be fortified by precipitation solidifying because of precipitation of the MgZn2 intermetallic stages. Furthermore, grain refinement and high dislocation density can also be opted for strengthening purposes. A low-temperature deformation enhances the dislocation density and also facilitates the grains recovery to strengthen the component. The present study combines artificial aging (at 120 °C) and sub-zero (∼−20 ˚C) temperature rolling to achieve strengthening. Various sequences and combinations of these mechanical and thermal treatments are performed and the effects of these treatments on the tribological characteristics of the alloy are studied by nano-scratch measurements. The tribological characteristics are indicated by coefficient of friction ( μ), plastic energy ( PE), recovery index ( η), recovery resistance parameter ( Rs), etc. of each sample. The widths of the scratch are further utilized to calculate the scratch hardness values ( Hs), wear resistance coefficients ( Rw) and the coefficient of wear ( K) with the help of Archard's equation.

Mitigation of heat treatment distortion of AA 7075 aluminum alloy by deep cryogenic processing using the Navy C-ring test

Heat treatment is a promising approach to advance the mechanical properties of AA 7075 aluminum alloy for aerospace structural applications. Quenching is commonly performed after solutionizing of AA 7075 aluminum alloy to impart supersaturated solid solution condition. It involves rapid cooling of the previously solutionized part to room temperature with water as a quenching medium. It leads to severe distortion of the structural part and deteriorates its surface integrity due to the high thermal residual stresses. This paper reports the distortion behavior of heat-treated AA 7075 aluminum alloy by implementing the standard Navy C-ring test. For precise measurements, the coordinate measuring machine (CMM) was used. Deep cryogenic treatment (DCT) was executed after conventional heat treatment (CHT) to reduce the tensile residual stresses and mitigate the distortion potential of AA 7075 aluminum alloy. Results showed significant improvement in surface finish and hardness of deep cryogenically treated AA 7075 aluminum alloy. It is attributed to the precipitation of fine spherical second phase particles distributed uniformly in the matrix. The distortion potential of heat-treated AA 7075 aluminum alloy is minimized by 30.7 % by deep cryogenic processing. It is correlated to the counterbalancing of tensile residual stresses in the heat treated part by compressive residual stresses ensued by deep cryogenic quenching.