Grain shape and size and structural and phase conditions modified by aluminum ion implantation in UFG titanium

The paper presents the transmission electron microscopy investigations of the granular state and the structural and phase conditions of commercially pure ultra-fine grain (UFG) titanium VT1-0 alloyed with aluminum ions. The UFG-titanium is obtained by the multiple uniaxial compaction with intermediate annealing. The ion implantation is carried out on Mevva-V.Ru ion source at ion-implantation dosages of 1·10{17}, 5·10{17} and 1·10{18} ion/cm{2}. The functions are constructed for the grain size distribution in longitudinal and cross sections; the average grain size and the grain anisotropy factor are determined in this paper. It is shown that the grain shape and size of titanium specimens are modified due to the ion implantation. With the increase of the ion-implantation dosage the anisotropy factor decreases three times. At 1·10{18} ion/cm{2} ion-implantation dosage the longitudinal grain size comes to 0.7 [mu]m. The phase composition of the alloy is detected after the ion implantation and its modification induced by the implantation dosage. The quantitative characteristics and locations of secondary [beta]-Ti, TiAl[3], Ti[3] Al, TiC and TiO[2] phases are ascertained during the investigations. It is shown that TiAl[3] and Ti[3] Al are ordered phases formed during the ion implantation on [alpha]-Ti grain boundaries. The volume ratios of these phases are detected and determined by the ion-implantation dosage. The volume ratios of [alpha]-Ti and secondary TiC and TiO[2] phases do not depend on the implantation dosage and range between 0.3-0.9 vol.%

Structure and phase composition of the superalloy on the basis of Ni-Al-Cr alloyed by Re and La

Qualitative and quantitative studies of the structure, phase composition, morphology of phase of the high-rhenium alloys additionally doped with La were carried out by TEM and SEM methods. The alloy was obtained by directional solidification method. It was shown that introduction of Re and La to an alloy leads to formation of new phases: [beta] and [chi] , which bring serious irregularities in the structure of quasicuboids of [gamma]'-phase

Structure and phase composition of deformed heat-affected zone of the weld steel St3

The paper presents the transmission electron microscopy (TEM) investigations of the structural and phase conditions of the heat-affected zone of welded joint modified by plastic deformation. Tensile tests are carried out on INSTRON-1185 testing system at room temperature and 370 MPa loading. TEMinvestigations are carried out nearby the joint between the deposited and base metal, namely the type St3 steel. It is shown that the degree of plastic deformation has an effect on the material morphology, phase composition, defect structure and its parameters. It is shown that plastic deformation has no qualitative effect on the material structure, however it modifies its quantitative parameters. With the increase of the deformation degree, the perlite component becomes incomplete and transforms at first, to a fractured perlite and then to ferrite, thereby decreasing the volume ratio of perlite. The polarization of the dislocation structure is observed that, nevertheless, does not lead to the internal stresses that induce the specimen fracture

The structure of heat-resisting alloy modified by thermal treatment and alloyed by rhenium and lanthanum

The paper presents the scanning and transmission electron microscope investigations of the structure, phase composition, and morphology of heat-resisting alloy modified by thermal treatment and additionally alloyed by rhenium and lanthanum. Rhenium alloy is obtained by the directional crystallization technique. The structural investigations are carried out for three alloy states, i.e. 1) original (after the directional crystallization); 2) 1150°С annealing during 1 h and 1100°С annealing during 480 h; 3) 1150°С annealing during 1 h and 1100°С annealing during 1430 h. It is shown that fcc-based [gamma]- and [gamma]'-phases are primary in all states of the alloy. [gamma]'-phase has L12 structure, while [gamma]-phase is a disordered phase. Rhenium and lanthanum are phase-forming elements. Investigations show that high-temperature annealing modifies the structural and phase conditions of the heat-resisting alloy