Characterizing the tensile behavior of double wire-feed electron beam additive manufactured "copper-steel" using digital image correlation

The paper presents the results of the evaluation of the mechanical characteristics of samples of multi-metal “copper-steel” structures fabricated by additive double wire electron beam method. The global and local mechanical characteristics were evaluated using uniaxial tensile tests and full-field two-dimensional digital image correlation (DIC) method. DIC revealed the peculiarities of the fracture stages: at the first stage (0.02<ε≤0.08) the formation of V-shaped shear lines occurs; at the second stage (0.08<ε≤0.15) transverse shear lines lead to the formation of a block structure; at the third stage (0.15<ε≤0.21) the plasticity resource ends in the central part of the two necks cracks are formed, and the main crack is the cause of the fracture of the joint. It is found that shear lines are formed first in copper and then propagate to steel. Electron microscopy proves that uniformly distributed iron particles could always be found in the “Fe-Cu” and “Cu-Fe” interfaces. Additionally, the evolution of average strain rates and standard deviations were measured (calculated) in the regions of necks in copper and steel regions. New shear approach shows that the most of angles for parallel shears components are ±45°, rupture angles are about 0°, and combined account of these two types of shears provides us additional discrete angles

Subsurface structural evolution and wear lip formation on copper single crystals under unlubricated sliding conditions

The crystalline lattice reorientation in copper single crystals resulted from friction-induced subsurface deformation has been studied by means of electron back scattering diffraction as well as optical microscopy. The results have been compared to those obtained earlier in uniaxial compression. The copper single crystals oriented by their normal load forces either along [110] or [111] have been subjected to sliding tests during which the friction force direction was varied to assess the friction force orientation dependence on the crystalline lattice reorientation and segmentation. The results of dry sliding tests showed that the plastic deformation in copper single crystals depended on the crystal's orientation with respect to both normal and friction forces. Crystalline lattice reorientation in wear lip formation has been studied including reorientation by ridge-kink formations

Structure, Mechanical Properties and Friction Characteristics of the Al-Mg-Sc Alloy Modified by Friction Stir Processing with the Mo Powder Addition

In this study, samples of Al-Mg-Sc alloy were investigated after friction stir processing with the addition of Mo powder. Holes were drilled into 5 mm-thick aluminum alloy sheets into which Mo powder was added at percentages of 5, 10, and 15 wt%. The workpieces with different powder contents were then subjected to four passes of friction stir processing. Studies have shown that at least three tool passes are necessary and sufficient for a uniform Mo powder distribution in the stir zone, but the number of required passes is higher with an increase in the Mo content. Due to the temperature specifics of the processing, no intermetallic compounds are formed in the stir zone, and Mo is distributed as separate particles of different sizes. The average ultimate strength of the composite materials after four passes is approximately 387 MPa in the stir zone, and the relative elongation of the material changes from 15 to 24%. The dry sliding friction test showed that the friction coefficient of the material decreases with the addition of 5 wt% Mo, but with a further increase in Mo content, returns to the original material values

Physical and mechanical properties of CuW20 composites synthesized by explosive compaction of bimetallic nanoparticles

The paper considers the physical and mechanical properties of bimetallic tungsten-copper powders after explosive compaction. This method is used to produce rather dense powder compacts from tungsten-copper nanoparticles. The structural analysis and the analysis of physical and mechanical properties of the obtained composites show that the pressure reduction and an increase in the time of explosive compaction considerably improve the composite hardness and mechanical properties

Friction Stir Processing of Additively Manufactured Ti-6Al-4V Alloy: Structure Modification and Mechanical Properties

This work explores the possibility of using friction stir processing to harden the Ti-6Al-4V titanium alloy material produced by wire-feed electron beam additive manufacturing. For this purpose, thin-walled workpieces of titanium alloy with a height of 30 cm were printed and, after preparation, processed with an FSW-tool made of heat-resistant nickel-based superalloy ZhS6U according to four modes. Studies have shown that the material structure and properties are sensitive to changes in the tool loading force. In contrast, the additive material’s processing direction, relative to the columnar grain growth direction, has no effect. It is shown that increasing the axial load leads to forming a -transformed structure and deteriorates the material strength. At the same time, compared to the additive material, the ultimate tensile strength increase during friction stir processing can achieve 34–69%

Structure, Mechanical Properties and Friction Characteristics of the Al-Mg-Sc Alloy Modified by Friction Stir Processing with the Mo Powder Addition

In this study, samples of Al-Mg-Sc alloy were investigated after friction stir processing with the addition of Mo powder. Holes were drilled into 5 mm-thick aluminum alloy sheets into which Mo powder was added at percentages of 5, 10, and 15 wt%. The workpieces with different powder contents were then subjected to four passes of friction stir processing. Studies have shown that at least three tool passes are necessary and sufficient for a uniform Mo powder distribution in the stir zone, but the number of required passes is higher with an increase in the Mo content. Due to the temperature specifics of the processing, no intermetallic compounds are formed in the stir zone, and Mo is distributed as separate particles of different sizes. The average ultimate strength of the composite materials after four passes is approximately 387 MPa in the stir zone, and the relative elongation of the material changes from 15 to 24%. The dry sliding friction test showed that the friction coefficient of the material decreases with the addition of 5 wt% Mo, but with a further increase in Mo content, returns to the original material values

Microstructure and Corrosion Resistance of AA4047/AA7075 Transition Zone Formed Using Electron Beam Wire-Feed Additive Manufacturing

A gradient transition zone was obtained using electron beam deposition from AA4047 wire on AA7075 substrate and characterized for microstructures, tensile strength and corrosion resistance. The microstructure of the transition zone was composed of aluminum alloy grains, Al/Si eutectics and Fe-rich and Si-rich particles. Such a microstructure provided strength comparable to that of AA7075-T42 substrate but more intense corrosion due to the higher amount of anodic Mg2Si particles. The as-deposited AA4047 zone formed above the transition zone was composed of aluminum alloy dendrites and interdendritic Al/Si eutectics with low mechanical strength and high corrosion potential

Characterizing the Tensile Behavior of Double Wire-Feed Electron Beam Additive Manufactured &ldquo;Copper&ndash;Steel&rdquo; Using Digital Image Correlation

The paper presents the results of the evaluation of the mechanical characteristics of samples of multi-metal &ldquo;copper-steel&rdquo; structures fabricated by additive double wire electron beam method. The global and local mechanical characteristics were evaluated using uniaxial tensile tests and full-field two-dimensional digital image correlation (DIC) method. DIC revealed the peculiarities of the fracture stages: at the first stage (0.02&lt;&epsilon;&le;0.08) the formation of V-shaped shear lines occurs; at the second stage (0.08&lt;&epsilon;&le;0.15) transverse shear lines lead to the formation of a block structure; at the third stage (0.15&lt;&epsilon;&le;0.21) the plasticity resource ends in the central part of the two necks cracks are formed, and the main crack is the cause of the fracture of the joint. It is found that shear lines are formed first in copper and then propagate to steel. Electron microscopy proves that uniformly distributed iron particles could always be found in the &ldquo;Fe-Cu&rdquo; and &ldquo;Cu-Fe&rdquo; interfaces. Additionally, the evolution of average strain rates and standard deviations were measured (calculated) in the regions of necks in copper and steel regions. New shear approach shows that the most of angles for parallel shears components are &plusmn;45&deg;, rupture angles are about 0&deg;, and combined account of these two types of shears provides us additional discrete angles

Features of Structure and Properties of Lap-Welded Joints of Aluminum Alloy Al–4Cu–1Mg with Titanium Alloy Ti–6Al–4V, Obtained by Friction Stir Welding

Lap-welded joints between Ti–6Al–4V and Al–4Cu–1Mg were obtained using water-cooling-bath friction stir welding at different FSW tool rotation rates. The increase in the tool rotation rate from 350 to 375 RPM leads to better plasticization of the titanium alloy, elimination of stir zone defects, better interlocking and bonding with the aluminum alloy as well as the formation of intermetallic Al–Ti compounds (IMC), preferentially of the Al3Ti type. Shear-loading testing showed the best result was at the level of 3000 N with 2 mm of displacement. Increasing the FSW tool rotation rate to 400 and 450 RPM resulted in the formation of more IMCs, which had a detrimental effect on both maximum load and displacement achieved in the shear tests

Development of a Multimaterial Structure Based on CuAl₉Mn₂ Bronze and Inconel 625 Alloy by Double-Wire-Feed Additive Manufacturing

This work studied the possibility of producing multimaterials consisting of aluminum bronze CuAl9Mn2 and nickel-based superalloy Inconel 625 by double-wire electron beam additive manufacturing. Samples with 5%, 15%, 25%, and 50% of the nickel-based alloy in aluminum bronze were produced for the research. The structural features of these multimaterials were analyzed, and tensile properties, microhardness, and dry sliding friction properties were measured. The results showed that 50% of the nickel-based alloy in the multimaterial composition provides the formation of a dendritic structure. Such a material shows worse values of ductility and wear resistance. Samples containing 5%, 15%, and 25% of Inconel 625 provide similar friction coefficient values, whereas, with increasing concentration of the nickel-based alloy, the material’s ultimate tensile strength and microhardness increase significantly