Tensile properties of chromium alloyed with silver

Tensile behaviors of chromium (Cr) and Cr alloyed with various contents of silver (Ag) have been studied in air at room temperature. The results show that adding Ag to Cr can greatly improve the latter’s tensile ductility: Cr-2 at. pct Ag alloy was subjected to about 23 pct tensile elongation at room temperature.     

Influence of zirconium addition on the microstructure,thermodynamic stability,thermal stability and mechanical properties of mechanical alloyed spark plasma sintered (MA-SPS) FeCoCrNi high entropy alloy

ABSTRACT

Equiatomic FeCoCrNi (Zr₀) and non-equiatomic FeCoCrNiZr_0.4 (Zr_0.4) high-entropy alloys (HEAs) were synthesised by mechanical alloying and spark plasma sintering. XRD analysis verified the formation of FCC and BCC solid solution phases in both alloys after 30?h of ball milling. While the SPS FeCoCrNi alloy contains both FCC and BCC solid solution phases, the FeCoCrNiZr_0.4 presents an FCC solid solution. The thermodynamic analysis showed that FeCoCrNiZr_0.4 is more stable with respect to the FeCoCrNi alloy. The phase stability of FeCoCrNiZr_0.4 was revealed up to ～800°C. The shear strength and hardness of the FeCoCrNi HEA improved with Zr addition. Failure analysis of the shear punch tested samples revealed a ductile fracture with dimple structure for FeCoCrNi and a brittle fracture with a smooth featureless surface for FeCoCrNiZr_0.4.     

Effect of combined deformation on the structure and properties of copper and titanium alloys

The effect of a combination scheme of severe plastic deformation and subsequent cold rolling or electroplastic rolling on the deformability, microstructural evolution, and mechanical properties of copper, titanium of various purities, and a titanium alloy of an equiatomic composition is studied. The combined deformation method is shown to create a number of new nanostructured and ultrafine-grained states with a high strength and ductility.     

Structure formation during the sintering of powder steels alloyed with copper,chromium, and phosphorous

The process of structure formation during the sintering of powder steels alloyed with copper, chromium, and phosphorous was investigated. The microstructure of the materials, and distribution of alloying elements in the iron grains, were studied by the methods of electron and scanning electron microscopy. The effect of dispersion of the ferrochromium powder on its solubility in iron was examined.Kirov Factory for the Manufacture of Articles from Metal Powder. Translated from Poroshkovaya Metallurgiya, Nos. 5/6, pp. 56–62, May–June, 1995.     

Structure and mechanical properties of chromium alloyed with magnesia and boron

Conclusions By alloying chromium simultaneously with magnesia and borides, it is possible to increase its high-temeprature strength and at the same time improve its low-temperature ductility. The best combination of mechanical properties is exhibited by alloys with boron contents of not more than 0.1 wt. %. The greatest increase in the short-time strength of chromium is brought about by alloying with tungsten. In longer periods of operation higher strength is shown by chromium alloyed with vanadium boride.Translated from Poroshkovaya Metallurgiya, No. 7(223), pp. 78–82, July, 1981.     

Effect of additions of zirconium,chromium, and nickel on the structure and characteristics of superplasticity of alloys of the Al-Zn-Mg-Cu system

By optical and transmission microscopy as well as by X-ray structural analysis, the structure and properties of alloys of the Al-Zn-Mg-Cu system with Ni, Zr, and Cr additions during superplastic deformation are investigated. It is shown that introduction of 0.26% Zr into the alloys leads to the formation of a nonrecrystallized or partially recrystallized structure in the billets. Such materials manifest the effect of superplasticity at t = 515°C in a range of deformation rates of (0.15–1.0) × 10^?2 s^?1, and the relative elongation reaches 450–680%.     

冷拉拔变形对纯铜组织及性能的影响

通过工业拉丝机对纯铜棒材进行多道次冷拉拔得到不同变形量的线材.对不同变形量的线材试样进行退火实验(400℃,1 h),研究组织形貌变化对其力学性能和电学性能的影响.试样的变形量由0增加至60％时,在拉拔方向上晶粒尺寸由101.3μm下降至17.6μm,截面方向上晶粒尺寸由103.4μm下降至16.4μm,晶粒呈现等轴状...     

Some properties of components from iron powder alloyed with 6% chromium

Summary The process developed at the Institute for thermal diffusion impregnation from point sources is simple and reliable, and permits production of iron-chromium alloy powders of any desired composition. Compared with parts of pure iron, constructional components obtained from these powders exhibit higher strength, ductility, and oxidation resistance.Translated from Poroshkovaya Metallurgiya, No. 8(56), pp. 28–33, August, 1967.     

Effect of surface treatment on the structure and high-rate dischargeability properties of ABs-type hydrogen storage alloy

Surface-treated MmNi_3.55Co_0.75Mn_0.4Al_0.3 alloy as negative electrode material of nickel-metal hydride battery was employed to improve the high-rate dischargeability. Surface treatment was realized by dipping and stirring the alloy into a HCl aqueous solution with various concentrations at room temperature. The microstructure of the alloy before and after surface treatment was analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electrochemical properties before and after surface treatment were comparedand the alloy treated in 0.025 mol/L HCl solution showed the optimal high-rate dischargeability.     

Phase composition, structure, and properties of aluminum materials mechanically alloyed with boron

The paper focuses on the formation of phase composition, structure, and properties of high-strength aluminum materials that are mechanically alloyed with boron and have a large effective thermal-neutron capture cross-section. A technology based on reactive mechanical alloying is proposed. It is intended to produce dispersion-hardened nanostructured materials in the Al-B system. Structural high-temperature materials with a low density and a great effective thermal-neutron capture cross-section can be obtained by complex alloying of aluminum with elemental boron (up to 40%) and B₂O₃ (1.5%). When the boron content reaches its maximum (40%), the strength of the material is σ_t = 380 MPa and σ ₁₀₀ ⁵⁰⁰ = 101 MPa; when the boron content decreases to 10%, the strength increases to σ_t = 560 MPa and σ ₁₀₀ ⁵⁰⁰ = 150 MPa.     

Formation of chromium coatings alloyed with nickel on diamond

The methods of x-ray phase analysis are used to study the composition of chromium — nickel coatings and metallizing mixtures (metal spraying compositions) as a function of the annealing conditions. The thickness of the coatings is calculated from the weight gain by diamond. It is shown that coatings are formed mainly by the transfer of chromium and nickel through the gas phase to the reaction surface (diamond or the outer surface of the coatings) and diffusion of carbon from the diamond (into the coating) which determines the phase composition of the coating: Cr₃C₂, Cr, Cr₇C₃, and Ni. Nickel appears in the metal spraying compositions because of the reduction of NiO by the carbon of chromium and carbon monoxide. The formation of the phases in the metal spraying compositions, which block the intensity of evaporation of chromium (due to NiO restoration with chromium) and of Ni(Cr) (due to the dissolution of chromium in nickel), is the factor that limits the growth of the coating. This is the main reason for the decrease in the thickness of the coating when nickel monoxide is added to the chromium metallizing mixture.Institute of Materials Science Problems, Ukrainian Academy of Sciences, Kiev. Translated from Poroshkovaya Metallurgiya, No. 1 (361), pp. 47–51, January, 1993.