Papers by Keyword: Yield Strength

Abstract: Pre-precipitate (cluster) strengthening is an integral aspect in the design of novel aluminum alloys. To investigate the impact of clusters on the strength of different aluminum alloys, Monte Carlo methods and the modified embedded atom method potential function were employed to simulate dilute aluminum-rich solid solutions, and these ten elements (silicon, magnesium, manganese, titanium, zirconium, chromium, iron, lithium, copper and nickel) were added as solute elements. The yield strength was evaluated and then the relationships among cluster size, cluster number, yield strength, and alloy compositions were analyzed. Finally, in the binary aluminum alloys the introduction of zirconium produces the largest yield strength among these ten elements, on the opposite side, the yield strength of Fe added alloy is the lowest. In most ternary aluminum alloys, after Mg, Zr and Li were added, the yield strength was increased compared to the results of the binary alloy, and the yield strength of Al-Li-Zr alloys is the largest in all ternary alloys. For multi-component aluminum alloy, the increase in type and number of elements resulted in fewer clusters, larger cluster size, and higher yield strength.

Abstract: Additive manufacturing (AM) is a process of generating prototypes or usable parts with minimum amount of material, technology, and time. The forerunner for technology and material for AM are Fused Deposition Method (FDM) and Polylactic Acid (PLA), respectively. There are numerous works in FDM devoted to studying the effect of processing conditions on the part strength. However, no significant effort has been made to develop an understanding of the effects of the nozzle diameter, extrusion temperature, infill percentage, infill pattern, and the number of outer shells in minimizing print time & raw materials without sacrificing significant part strength. This research intends to conduct a multi-objective approach in identifying significant factors that will affect the target response. It was observed that nozzle diameter, wall thickness and infill density are the significant factors that may affect strength, build time and material consumption. In Scanning Electron Microscope (SEM) results, it was observed that the more voids seen at fracture would result to lesser strength. Lastly, a regression equation was generated to guide future researchers and end-users in predicting response in consideration of the factors (or parameters) involved in this experiment.

Abstract: In the present study, Fe-0.2C-1.2Si-10.3Mn-3.4Al-0.33V multiphase steels were prepared by two different processing including intercritical annealing and warm rolling plus heat treatment. The microstructure changes induced by working processes and their effects on mechanical properties were investigated. By establishing the yield strength contribution model of each phase, the contribution of various strengthening mechanisms to the yield strength of each phase is calculated. The calculated results suggest that warm rolling plus heat treatment process improves the grain boundary strengthening, solid solution strengthening, precipitation strengthening and dislocation strengthening of each phase, and improves the yield strength.

Abstract: This paper presents the results of research and test of the self-designed and manufactured rotary friction welding machine. Tensile test results show that the tensile strength of the material after welding is satisfactory according to the standards of the material; the elongation is within the elongation limit of the welding specimen; the yield limit is greater than the minimum yield limit of the material. The parameters of the welding equipment are guaranteed according to the design requirements.

Abstract: The issues of determining the Mayer index depending on the parameters of strain hardening of an elastoplastic body described by the Hollomon equation are considered. The analysis of expressions connecting the engineering uniform deformation with the Mayer index is carried out. A new expression is obtained, a particular case of which is the result obtained by V.M. Matyunin et al. Applying the ratio of the maximum Mayer hardness to the Brinell hardness, the relationship of the ultimate strength to the Brinell hardness, and the Hollomon equation, a new expression of the Mayer law is obtained. The description of the radius of the contact area by a power function of the depth of the indenter insertion allowed us to represent the Mayer index as a ratio of known parameters obtained by finite element modeling for other purposes. The graphical dependences of the results obtained are presented.

Abstract: This paper presents the results of a study of changes in mechanical properties, namely tensile strength, yield strength and elongation when drawing a wire from NP2 nickel (Ni 99.6). The wire samples taken along the drawing route were tested for tension. Based on the test results obtained, graphs of changes in tensile strength, yield strength and elongation were plotted depending on cold work. The approximation of the graphs made it possible to obtain equations for the change in tensile strength (UTS), yield strength (0.2 US) and elongation (δ) depending on cold work (ɛ∑). The obtained dependences are recommended to be used to predict the mechanical properties of nickel wire during drawing and when developing software for designing resource-saving drawing routes.

Abstract: The purpose of the study was to predict the mechanical and toughness properties of Ni-modified alloy steels by adding 1.55%, 1.75%, and 1.95% of Ni-content to the existing Cr-Mo alloy steel of transmission gear material. Typically transmission gears have been working under severe working situations of loads and rotations. Due to these situations, the properties and qualities of gear materials are highly affected consequently, fatigue failure is instigated. So, improving the mechanical and toughness properties of the existing gear material is very vital and compulsory since these properties have a direct impact on gear fatigue failure. Investigations have been done on determining the mechanical and toughness properties of the Ni-modified Cr-Mo alloy steels, through ANN modeling prediction by associating the complex relation of input (chemical composition, tempering temperature) and output parameters (mechanical and toughness properties), and verified by experimental test approaches. Explored these materials property with ANN modeling and experimental test show that the more Ni-content added to the Cr-Mo alloy steel, the higher the ultimate and yield strength can achieve at every instant of tempering temperature. Likewise, fracture toughness, impact toughness, and percent of retained austenite of these materials were also investigated thoroughly as tempering temperature varies. Thus, a 1.55 % Ni-modified Cr-Mo alloy steel has a higher value of both impact toughness and fracture toughness compared with other Ni-modified alloy steels. Similarly, surface hardness was slightly decreased as the amount of Ni-content added increased at each instant of tempering temperature. Lastly, based on both predicted and experimental results, 1.55 % of Ni-modified Cr-Mo alloy steel showed a better combination of mechanical and toughness properties. Keywords: ANN modeling; Yield strength; Ni-modified; Tempering temperature; Fracture toughness; Surface hardness

Abstract: The problem urgency for determining the optimal rolling and heat treatment schedules for providing the required indices of heavy plates physical and mechanical properties is shown. The use of statistical mathematical models for solving this problem is substantiated and the methodology for their design is described. Statistical mathematical models were designed using the mathematical statistics methods and Data Mining tools to determine the yield strength, ultimate tensile strength and percent elongation for 10Mn2VNb steel plates rolled under 3600 heavy plate mill conditions. Software for the numerical implementation of these statistical mathematical models has been developed. Applied software has been developed for the numerical implementation of the statistical mathematical models for predicting the heavy plate’s mechanical properties, and high calculation accuracy has been confirmed with the ones help: 95.82% for the yield strength, 96.78% for the ultimate tensile strength, and 91.48% for the percent elongation. The regularities of the influence for finish rolling factual temperature in the finishing stand of 3600 heavy plate mill and the plate thickness on 10Mn2VNb pipe steel physical and mechanical properties were identified by processing the database and using the designed software.

Abstract: The authors present the results of evaluating the distribution of plastic properties on the height of a log ingot with the diameter of 145 mm, obtained by means of semi-continuous casting, from the aluminum alloy AD31. The authors study semi-continuous alloys of three manufacturers. One part of ingots was obtained with the use of only primary aluminum, secondary raw materials and secondary raw materials with the addition of primary aluminum. With the purpose of stabilizing the process of presswork the authors define the values of yield stress in the ingot lower and upper parts and study its microstructure. The research was conducted for the ingots without thermal treatment after accelerated homogenization. It is shown that the ingots, produced with the use of primary aluminum only, have less scattered plastic properties in terms of the height. That is why, for the case of press-working the items with thin components, it is reasonable to use the ingots from primary aluminum.

Abstract: In this paper the methods of mechanical testing of metal and the possibility of their implementation, using mathematical modeling by the finite element method in Deform software package, are considered. As the studied parameters, both the strength indicators (yield strength, tensile strength, Brinel micro-hardness), and the plasticity indicator (the number of kinks before the crack is formed), were studied. The values obtained in the simulation have a very high convergence with the real data.