Papers by Keyword: Rotary Swaging

Abstract: The article presents the results of the study of microstructure, mechanical properties, corrosion resistance and fatigue strength of the Zn-1%Mg and Zn-1%Mg-0.1%Ca alloys, processed by rotary swaging (RS). It is shown that the grain refinement leads to an increase in the strength of the alloys up to 196 ± 4 and 218 ± 6 MPa for the Zn-1%Mg and Zn-1%Mg-0.1%Ca alloys, respectively. The ductility of the Zn-1%Mg and Zn-1%Mg-0.1%Ca alloys also increases up to 5.7 ± 2.2 and 7.0 ± 0.7%, respectively. The structure caused by RS does not affect the corrosion potential of both investigated alloys, but changes the corrosion current density, decreasing it for the Zn-1%Mg alloy and increasing it for Zn-1%Mg-0.1%Ca. The fatigue limit of the Zn-1%Mg and Zn-1%Mg-0.1%Ca alloys after RS is equal to 115 MPa and 130 MPa, respectively.

Abstract: The paper focuses on the analysis of microstructure and mechanical properties of the Ti alloy VT8М-1 (Ti-5.3Al-4.0Mo-1.2Zr-1.3Sn-0.2Si) in an ultrafine-grained (UFG) state subjected to a long-term annealing at a service temperature of (≤ 450°С). A rotary swaging (RS) was used to process an UFG state in the material. The precipitation of disperse silicides of S2 was observed after the deformation by RS. It has been shown that the UFG alloy retained its high level of thermal stability and enhanced mechanical properties after long-term annealing up to 500 hours. The role of disperse silicides in both strengthening and stability of mechanical properties in the alloy after long-term annealing is discussed.

Abstract: The work addresses the microstructural evolution and mechanical properties of the ultrafine-grained (UFG) VT8M-1 subjected to isothermal die forging (IDF) and subsequent thermal treatment. An UFG microstructure with a mean size of secondary grains of about 0.3 μm was processed by a rotary swaging (RS) at Т=780°С. The ultimate tensile strength (UTS) of the alloy increased by 23% as compared to an initial state due to the formation of an UFG microstructure. It has been shown that isothermal die forging of the UFG alloy at Т=780°С leads to the growth of secondary phase grains by 0.7 μm. Subsequent heat treatment of the forged billets leads to hardening of 11%, which can be attributed both to the formation of additional interphase α/β boundaries at the precipitation of a tertiary α-phase and silicide dispersion.

Abstract: Characterization of advanced materials by neutron powder diffraction provides information not accessible by other techniques. Thanks to the low absorption of neutrons, the bulk of the material and large-grain samples can be investigated, moreover in situ at elevated temperatures. The neutron diffraction use is demonstrated on two types of technologically important materials: Ti-Zr alloy and Co-Re high temperature alloy. In Ti-Zr alloy, the residual stress relief and microstrain evolution after ECAP was established. Boron influence on TaC strengthening precipitates in Co-Re high temperature alloys was shown not to be significant at the foreseen alloy operation temperatures, although boron content has a strong influence on the matrix phase.

Abstract: The study investigates a W93Ni6Co1 tungsten heavy alloy rotary swaged at 20 °C and 900 °C with the aim to optimize its mechanical properties. Deformation behaviour was predicted via numerical simulations and subsequently verified via experimental swaging. The results showed that swaging at 900 °C led to substantial increase in ductility (24% elongation after the first pass), whereas swaging at room temperature primarily increased the UTS (up to 1800 MPa after the second pass). Among the key differences between both the swaging temperature modes were the different substructure developments; the higher swaging temperature imparted activation of softening processes within the γ matrix and homogenization of residual stress. The W agglomerates within both the swaged pieces featured the presence of <101> and <001> preferential orientations.

Abstract: Thorough analyses were focused on characterization of deformation behaviour of the component metals, orientations of their structural units, and development of intermetallic phases on the interfaces within Cu/Al clad composites produced by rotary swaging at 20 °C and 250 °C. The shapes of the cross-sections of Al wires within the composites were affected by the increasing total imposed strain more at 250 °C, the 250 °C composites also exhibited formation of intermetallics at higher swaging degrees. Intermetallics decreased the electric conductivity, which was generally higher for 20 °C samples, however, the conductivity was also affected by the occurring deformation hardening/softening. The average microhardness of Cu exceeded 100 HV for all the samples.

Abstract: This study investigated the prospective application of the advantageous intensive plastic deformation method of rotary swaging for production of Al-Cu composite wires. Such materials are perspective to be used within a wide range of commercial and industrial branches, from transportation to electrotechnics. Cu-Al laminated wires with two unique different stacking sequences were rotary swaged down to 5 mm diameter at room temperature to minimize the development of brittle intermetallics at the interfaces. The analyses primarily focused on the mutual comparison of both the stacking sequences (Al sheath reinforced with Cu wires vs. Al sheath and Al core reinforced with Cu inter-layer) from the viewpoints of mechanical properties, sub-structure development, and occurrence of residual stress. While the individual Cu wires exhibited bimodal structure and the presence of residual stress within the growing grains, the Cu inter-layer featured recrystallized grains and homogeneous stress distribution. The mechanical properties for both the composites were enhanced by the swaging technology; the composite reinforced with Cu wires exhibited slightly higher ultimate tensile strength than the one with Cu inter-layer (258 MPa vs. 276 MPa). However, the latter featured significantly higher plasticity.

Abstract: The article presents the results of an investigation of microstructure, mechanical properties and corrosion resistance of magnesium alloy WE43 processed by rotary swaging. The resulting microstructure is characterized by an average size of structural elements of 0.5 – 0.8 μm. The grain refinement leads to an increase in the strength of the alloy to 393 – 416 MPa while the tensile elongation stays at a level of 7 – 12.5%. The microstructure produced by rotary swaging does not lead to deterioration of the resistance of the alloy to electrochemical and chemical corrosion.

Abstract: The main reason why new technologies and treatment procedure are being developed is to attain special mechanical properties. However, these developments are nowadays done on a small material volume either using some laboratory simulators, applying sever plastic deformation procedures or chemical composition screening for multicomponent alloys development by laser or electron beam melting. In all these application a small volume of the material assessed is available and standard procedures for crucial mechanical properties determinations are not applicable. Thus small size techniques should be applied. There has been extensively used small punch test technique (SPT) for those cases in recent years. This technique is mainly based on the evaluation using correlation between standard and SPT tests for considered material. In cases when insufficient material volume is available, those correlations cannot be established and thus comparative evaluation only can be carried out. This kind of evaluation is insufficient for the contemporary purposes, when full material potential is to be utilized. Therefore, procedures providing results directly comparable with standard specimens are being developed. Fundamental properties are those determined from tensile tests. The current paper is presenting application of developed miniature tensile test specimen method to materials after SPD processes. Quasi static properties determination is shown here for Magnesium and Titanium alloys for ECAP and Rotary Swaging SPD techniques. The results obtained from testing can be used not only for a direct material properties assessment and comparison, but also as input data for FEM codes, significantly increasing the materials considered application potential assessment.

Abstract: Wires with 1 mm initial diameter have been reduced between 10 and 64 percent at different temperatures and strain rates by infeed rotary swaging, which is an incremental cold forming process mainly used for rods and pipes. The volume fraction of martensite in the deformed wires has been determined by X-Ray diffraction and by magnetic induction for different processing parameters. Measurements show that for already small percentage of reduction, martensite is present in the wires and its amount changes with the strain rate and temperature. While for smaller strain rates at room temperature the formation of martensite is promoted, it is restrained for higher strain rates and higher temperatures. Results also reveal that the martensite distribution in the sample is inhomogeneous. Further investigations have been made to analyze the microstructure by optical microscopy and to determine mechanical properties by tensile testing.