Properties of the Ti40Zr10Cu36Pd14 BMG modified by Sn and Nb aqdditions

The results of investigation of the influence of additions of 2 and 3 at.% of Sn and simultaneously of Sn and 3 at.% Nb on microstructure and properties of the bulk metallic glasses of composition (Ti40Cu36−x Zr10Pd14Sn x )100−y Nb y are reported. It was found that the additions of Sn increased the temperatures of glass transition (T g), primary crystallization (T x ), melting, and liquidus as well as supercooled liquid range (ΔT) and glass forming ability (GFA). The nanohardness and elastic modulus decreased in alloys with 2 and 3 at.% Sn additions, revealing similar values. The 3 at.% Nb addition to the Sn-containing amorphous phase decreased as well all the T g, T x , T L, and T m temperatures as ΔT and GFA; however, relatively larger values of this parameters in alloys containing larger Sn content were preserved. In difference to the previously published results, in the case of the amorphous alloys containing small Nb and Sn additions, a noticeable amount of the quenched-in crystalline phases was not confirmed, at least of the micrometric sizes. In the case of the alloys containing Sn or both Sn and Nb, two slightly different amorphous phase compositions were detected, suggesting separation in the liquid phase. Phase composition of the alloys determined after amorphous phase crystallization was similar for all compositions. The phases Cu8Zr3, CuTiZr, and Pd3Zr were mainly identified in the proportions dependent on the alloy compositions

Evolution of microstructure and residual stress during annealing of austenitic and ferritic steels

International audienceIn this work the recovery and recrystallization processes occurring in ferritic and austenitic steels were studied. To determine the evolution of residual stresses during material annealing the nonlinear sin 2 ψ diffraction method was used and an important relaxation of the macrostresses as well as the microstresses was found in the cold rolled samples subjected to heat treatment. Such relaxation occurs at the beginning of recovery, when any changes of microstructure cannot be detected using other experimental techniques. Stress evolution in the annealed steel samples was correlated with the progress of recovery process, which significantly depends on the value of stacking fault energy

Creation of wear-resistant near-surface-layers with inhomogeneous structure on NiTi alloy by ion implantation technology

In the present study we report the changes in the modified near-surface layer on NiTi shape memory alloy, caused by ion implantation as well as their influence on the structure and mechanical properties of this material. Experimental results of an inhomogeneous structure and tribological properties of implanted NiTi are discussed in this paper

Thermal induced structural and magnetic transformations in Fe_{73.5−x}Ce_{x=0,3,5,7}Si_{13.5}B_9Nb_3Cu_1 amorphous alloy

Structural and magnetic properties of amorphous and partly crystallized Fe_{73.5−x}Ce_{x=0,3,5,7}Si_{13.5}B_9Nb_3Cu_1 alloys, were analysed in the temperature ranging from RT to 800 °C with scanning calorimetry and magnetometry. The Fe(Si) and Fe(B) structures were identified and characterised with set of crystallization temperatures and activation energies. Also, Curie temperatures for amorphous and for crystalline structures were determined and analysed as functions of Ce content

Microstructure, Thermal and Mechanical Properties of Refractory Linings Modified with Polymer Fibers

The reduction in the inherent brittleness of coatings applied on parts of ceramic shielding used for continuous steel casting (CSC) processes is highly desired, since it can significantly diminish losses occurring during post-application handling and mounting. One of such coatings, prepared mostly from fused silica, ludox, tabular alumina, chamotte, cenospheres, dextrine and aluminum powder, is known commercially as Thermacoat™. The present experiment is focused on the effect of the modification of its composition by rising the content of the cenospheres (max. 2.5 wt.%) or by introducing up to 1.5 wt.% of polymer Belmix™ fibers (~34 μm diameter/12 mm length) on the microstructure and mechanical properties. The maximum amount of introduced additions was limited by the accompanying loss of mass viscosity, which must allow for deposition through immersion. Next, the differential scanning calorimetry and differential thermogravimetric analysis techniques were employed to evaluate the extent of the weight change and heat response of the mass during the drying and annealing stages. The dried materials’ microstructure was investigated with light and scanning electron microscopy, while the chemical composition was studied by energy dispersive spectroscopy. Finally, a three-point flexural bending method was used to determine changes in the material mechanical properties. The performed experiments proved that the small addition (~1 wt.%) of polymer fibers is sufficient for the significant improvement of the Thermacoat™ green mechanical strength at ambient temperature, presenting a reproducible ultimate flexural strength of ~0.2 MPa