A REVIEW ON THE EFFECTS OF THE REDUCTION RATIO AND THE DIE ANGLE ON THE PROPERTIES OF EXTRUDED Al-Zn-Mg ALLOY

Developing aluminum with good mechanical properties like hardness, tensile strength, and normal flow stress, Equal Channel Angular Extrusion (ECAE) method has been suggested as a suitable metal forming process. The load applied and extrusion temperature normally influences the flow stress behavior in extruded products and determine their mechanical properties. Consequently, how these factors affect mechanical behavior and flow stress of Al 6063 processed by ECAE was examined in this study. Extrusion temperatures were 350°C, 425°C, and 500°C with die angles of 130°, 140°, and 150°. 5 mm/s of ram speed was applied. Each extrudate's tensile strength and hardness were measured using a Universal Testing Machine and a Rockwell hardness tester. Samples with equal dimensions and properties were also modeled using the Qform software at the extended die angle and temperature for proper analysis of flow stress in the extrudates. According to experimental results, the temperature had a greater effect on the tensile strength and hardness of the billet than the die angle. The extrudates' grains also became finer as the billet temperature rose. Simulation findings showed that higher billet temperature led to a decrease in the extrudates' flow stress. The simulation also demonstrated that billet temperature had a greater impact on extrusion load than die angle, with a maximum extrusion load of 5.5 MN being attained at 350 °C.

On the possibility to reduce ECAP deformation temperature in magnesium: Deformation behaviour, dynamic recrystallization and mechanical properties

Fabrication of aluminum/copper clad composite using hot hydrostatic extrusion process and its material characteristics

The article presents the results of a study of wire drawing in a monolithic die. In the simulator of metal forming processes QForm, which is based on the finite element method, studies were carried out on drawing wire from steel grade 10 (1.1121) ∅3.0 mm from a billet ∅3.5 mm in the absence of friction at the contact of a monolithic die-billet. During the simulation, the influence of die angles 6, 8, 10, 12, 14 and 16° on the stress-strain state, strain rate and drawing force was studied. Research results have shown that: an increase in the die angle from 6° to 14° stress mean in the deformation zone changes its sign from compressive to tensile; at a die angle 8°, uniform mean stresses are created in the workpiece section; by reducing the angle of the drawing die in the wire section, uniform compressive deformations can be achieved; the strain rate increases with an increase in the die angle and leads to an increase in the resistance to deformation, which in turn leads to an increase in the drawing force. In the production of wire, when choosing drawing routes and determining single strains, it is necessary to consider die angles, since their influence on the drawing process and the quality of the wire is essential. KeywordsSimulation analysisWireDrawing machinesDieDeformation zoneDrawing speedStrain rateTemperature

A two step forging route was employed for Alloy 718 pancake forging. The effect of forging parameters on the evolution of microstructures within the pancakes during deformation was evaluated by metallographic observations. With the critical forging parameters of the dynamic recrystallization obtained by compression tests, FE simulation can effectively be utilized to predict detailed variations of the microstructures due to dynamic recrystallization for all forged pancakes. The distribution of forging parameters within a work piece is shown to be important in determining final grain sizes. Introduction One or two step forging processes are routinely employed for superalloy disk forging. Two step forging may be used especially for complex geometry forging of a superalloy disk with a uniform microstructure and properties. Depending on the forging temperature and post treatment, Alloy 7 18 can be grouped into three different types; i.e, standard, high strength and direct age versions[l]. Standard 718 is finish-forged well above the 6 (Ni3Cb) phase solvus temperature between 1038% and 1066% to make use of its reasonably good forgeability. The resulting grain size is ASTM 4-6. High Strength 718 is forged initially above the 6 solvus temperature, but finished in the end slightly below the 6 solvus temperature, resulting in a final grain size of ASTM 8 or finer. Direct-age 718 is finish-forged even at lower temperatures below the 6 solvus temperature followed by the conventional direct aging treatment, resulting in a finer grain size less than ASTM 10 with various mechanical properties; such as tensile strength and LCF properties. The selection of the different forging routes is determined by the design requirements of microstructures and mechanical properties. The change in microstructures is closely related with dynamic and static recrystallization during forging or post heat-treatment[2]. The recrystallization behavior is influenced by process variables such as the forging temperature, strain rate, initial grain size and amount of deformation[3]. The aim of this research is to investigate the effect of strain distribution on the final microstructure in the two step forging process. FEM simulation was carried out to predict the evolution of microstructures. Material Experimental Procedure The material used in this study was the premium quality Alloy 718 of high Nb content. The Superalloys 7X3,625,706 and Various Derivatives Edited by E.A. Loria The Minerals, Metals &Materials Society, 1997

In this paper, the microstructure and mechanical properties of AA7075 with a coarse-fine-grained laminated microstructure produced by spark plasma sintering (SPS) and the cyclic extrusion severe deformation (KOBO) technique were investigated. It was found that an inhomogeneous grain microstructure was formed from coarse and fine grains by the SPS process and then was transformed into a coarse-fine-grained laminated microstructure by means of KOBO extrusion at room temperature. The grain refinement during KOBO extrusion resulted in a fine grained laminated microstructure created due to the formation of low-angle grain boundaries (LAGBs), followed by dynamic recrystallization, leading to high-angle grain boundaries (HAGBs). The EBSD analysis results reveal the formation of a deformed and partially recrystallized ultrafine grain microstructure owing to the generation and development of shear bands during KOBO extrusion. The ultimate tensile strength (UTS) of the AA7075 alloy rose after SPS-KOBO severe deformation up to 422 MPa, with high strains of about 33%. The obtained results clearly show that the SPS-KOBO extrusion technique allows a bimodal laminated fine gradient grain microstructure to be obtained due to deformation and dynamic recrystallization, which result in both high strength and good ductility. The new heterogeneous AA7075 alloys obtained by the SPS-KOBO combined techniques demonstrate that microstructural heterogeneities can assist in overcoming the strength–ductility trade-off.

The need to optimize the process parameters in Electrical Discharge Machining (EDM) for aged AA7075 Metal Matrix Composites (AAMMCs) is evident as it impacts various aspects such as mechanical properties, tool wear, surface finish, integrity, precision, accuracy, process stability, process consistency, and cost-effectiveness. In this study, aluminium alloy AA7075 was chosen as the matrix material because of the need to enhance its mechanical properties. Titanium Carbide (TiC) was chosen as the reinforcing material owing to its superior mechanical properties. Therefore, TiC holds the capability to improve the mechanical attributes of AA7075. The selection of the stir cast method for the manufacturing of AA7075/TiC (0, 4, 8, 12, and 16 wt.%) was based on its ease of fabrication, ability to achieve a uniform distribution of reinforcements, reduced susceptibility to oxidation and porosity, and improved control over the microstructure. This AA7075/12wt.%TiC MMC underwent an aging process at 520 °C for 180 min and was subsequently cooled within the furnace environment. The density of the aged and non-aged AA7075/TiC-based composites was determined through a density test using the Archimedes’ principle. Microhardness testing was conducted on the non-aged and aged AA7075-based MMCs employing a Vickers microhardness tester. Tensile strength and compressive strength of the aged and non-aged AA7075-based MMCs were determined by the usage of a universal testing machine (UTM) and a compression testing machine (CTM). The optimal combination of the manufactured AA7075/TiC MMCs was determined based on their mechanical properties. The most effective combination was identified as AA7075/12wt.%TiC MMC due to its superior values in hardness, tensile strength, compressive strength, and density compared to other combinations. The aging process aimed to enhance the mechanical properties without the need for additional reinforcements. EDAX and X-ray Diffraction Analysis (XRD) tests were employed to determine the weight percentage of the matrix and reinforcements and to identify the formation of precipitates in the AA7075/12wt.%TiC composites. The SEM equipment was utilized to verify the uniform distribution of titanium carbide in the matrix material AA7075. Optimization of EDM process parameters for aged AA7075/12wt.%TiC composite was carried out using Taguchi design-based Grey Relational Analysis (GRA). The selected input parameters for the optimization included the chromium concentration (g×l-1), current (amps) and pulse-on time (µs). The response parameters chosen for optimization were surface roughness (SR) and tool wear rate (TWR). The sequence of influencing EDM input parameters is chromium concentration, pulse on time and current. The optimized EDM process parameters were 8 g×l-1 chromium concentration, 5 amps current and 240 µs pulse on time and the corresponding response were 0.198 TWR and 1.56 SR.

In this paper, an extensive direct extrusion program was designed to experimentally investigate the effects of die bearing geometry parameters with a view to achieving reduced extrusion loads and product deflection. Using soft aluminiumalloy as extrusion material, flat and conical pocket die bearing geometries were considered, and geometry parameters of die angle, bearing length, pocket depth and offset were varied to obtain corresponding responses of extrusion pressure and extrude deflection. Results showed that for conical pocket geometry, increasing entrant angle reduced extrusion pressure to a minimum value at the included die angle of 90°, and then increased gradually with further increase in die angle. Extrudes deflections are reduced as die angle is increased. Increasing the die bearing length increased extrusion pressure but extrudes deflection is reduced. For flat pockets, increasing the pocket depth increased extrusion pressure, but for conical pockets, extrusion pressure is reduced. For both geometries, extrudes deflection is reduced as pocket depth is increased. Both extrusion pressure and extrudes deflection are reduced increasing pocket offset. It is concluded that extrusion pressure and extrudes deflection can be controlled using these die geometry parameters. Better flow conditions are however obtained with conical die geometries to achieve minimized extrusion loads and product curvature.

Recently, a processing technique for applying plastic deformation to a solid wood has been developed. In this study, in order to clarify the effect of die-angle on the extrusion force of a solid wood, the extrusion load with or without lubricant for different die angle was investigated. Solid woods (Japanese cypress) were impregnated with thermoplastic binder (acrylic resin) to improve its fluidity during extrusion. To increase affinity with acrylic resin, the woods were hydrophobized by acetylation before the impregnation. Then the impregnated woods were extruded in a radial direction through the square-shaped dies having different angle (2α = 20°, 30°, 40°, 50°). The results obtained were as follows: The extrusion load was clearly decreased by using the lubricant in every die angle. The results of the no-lubricant condition showed that the extrusion load increased with the decrease in die angle. On the other hand, the extrusion load was little affected by the die angle in the lubricant condition. These results indicated that the extrusion load was strongly affected by the friction between the wood specimen and the tapered die in the no-lubricant condition. Assuming that plane strain condition (no strain in the longitudinal direction of the material) applies to the extrusion, the experimental result was well explained by the theoretical result.

Mechanical properties of electron-beam-melted biomedical Co–Cr–Mo–N alloys can be improved by the grain refinement from reverse transform treatment, which transforms a low-temperature strong ε-phase into a high-temperature ductile γ-phase. Although mechanical properties of alloys consisting of a single ε- or γ-phase have been previously reported on, those comprising mixed ε- and γ-phases have not yet been investigated. Herein, the heat treatment conditions of the Co–28Cr–6Mo–0.11N alloy were determined to control the phase fraction while obtaining fine grains in the mixed phases with superior mechanical properties. The phase transformation behavior was analyzed. Superior mechanical properties were observed in the mixed phases containing 70 pct γ-phase and 30 pct ε-phase. The tensile and yield strengths were higher, and the elongation was approximately the same, compared to that of the single γ-phase. Moreover, the 30 pct ε-phase mixed-phase material obtained during the γ → ε heat treatment had a smaller overall average grain size and showed superior mechanical properties than that obtained during the ε → γ heat treatment. This study is expected to facilitate the application of biomedical Co–Cr–Mo–N alloys with fine grains and superior mechanical properties obtained via heat treatment.

The Differential Speed Rolling (DSR) process is a severe plastic deformation method used in the production of microstructured materials with both high deformation and superior mechanical properties. This study has focused on determining the springback behavior and formability of the materials obtained by using the DSR method after the V bending process. Rolling processes were carried out at 4 different rolling speed ratios (1.0, 1.33, 1.66, and 2.0), 25% thickness reduction ratio, and 2 different rolling temperatures (room temperature and 580 °C). Then, the rolled sheet materials were bent using 3 different bending die angles (60°, 90°, 120°). As a result of this study, the greatest plastic deformation was reached at a speed ratio of 2.0 at 580 °C. Again, the lowest springback was obtained at 580 °C. As the die angle increased, the springback decreased. Springback has occurred in the bending process of all sheet materials obtained by rolling. In the bending process of the unrolled sheet material, both spring-forward and springback events were observed depending on the die angle.

Additive friction stir deposition of SS316: Effect of process parameters on microstructure evolution

Extrusion, among other types, is one of the most important forming processes due to its high productivity, lower cost and its good ability to improve the physical and mechanical properties of extruded materials. FE simulation was carried out on ABAQUS software ver.6.9. to study the distribution of stress and temperature which created through the extrusion process. The results of present study are accentuated that, there is a complicated relationship between stress and temperature distribution relative to die angle and friction coefficient. It was found, in the range of tested cases, at friction coefficient of more than ( 0.08 ), for ( 45o ) die angle, the maximum value of temperature is twice higher than that of ( 75o ), hence the die angle has more significant effect on state of stress and temperature than that of friction coefficient. Nevertheless, a high die angle ( α = 75o ) emerged low value of maximum temperature due to easily flow of material toward the die orifice. Furthermore, there are a gradual increasing of vonMises criterion and temperature with increasing the friction coefficient while they are decreasing with increasing the die angle.

Laser additive manufacturing of Zn metal parts for biodegradable applications: Processing, formation quality and mechanical properties

Theoretical and experimental study of die angle, and extrusion speed effect on relative extrusion pressure of annealed AA6061 aluminum alloy have been carried out in this research. Two theoretical fields have been employed, rigid-plastic field and mixed field, to predict the relative extrusion pressure. A FORTRAN program has been developed to calculate the relative extrusion pressure and its compounds. The tests have been conducted with various, die angle (30°,60°,90°,120°,150°) and various extrusion speed (10,7,3) mm/min.The results showed an increase in shear power and friction power with increasing die angle, while no effect was observed on the internal power of deformation. It was also found that the relative extrusion pressure, the inhomogeneous strain, and the shear strain across the section increase as the die angle and extrusion speed increase. Experimental tests showed that the optimum die angle was 60° while the optimum die angle was between 35°-90° and 46° according to the mixed field and the rigid- plastic field respectively.