The Study of the Fine Structure of Ti-Al Coatings on the Surface of Ti, Obtained by Mechanical Alloying

The work is devoted to the study of structural-phase transformations in composite coatings (Ti-Al)+Ti during mechanical alloying. The data on the structural-phase states of (Ti-Al)-Ti coatings after mechanical alloying have been obtained, confirming the mechanism of formation of the modified layer due to deformation compaction of powder particles on the titanium surface under mechanical action. As a result of mechanochemical fusion, a TiAl3 phase with a bcc lattice (I 4/mmm structure) was detected, which corresponds to the stable state of the TiAl3 alloy. Under conditions of mechanical alloying of the structure, I4/mmm transforms into the L12 structure, which corresponds to the metastable state of TiAl3

Mechano-Chemical Properties of Electron Beam Irradiated Polyetheretherketone

In this study, the mechano-chemical properties of aromatic polymer polyetheretherketone (PEEK) samples, irradiated by high energy electrons at 200 and 400 kGy doses, were investigated by Nanoindentation, Brillouin light scattering spectroscopy and Fourier-transform infrared spectroscopy (FTIR). Irradiating electrons penetrated down to a 5 mm depth inside the polymer, as shown numerically by the monte CArlo SImulation of electroN trajectory in sOlids (CASINO) method. The irradiation of PEEK samples at 200 kGy caused the enhancement of surface roughness by almost threefold. However, an increase in the irradiation dose to 400 kGy led to a decrease in the surface roughness of the sample. Most likely, this was due to the processes of erosion and melting of the sample surface induced by high dosage irradiation. It was found that electron irradiation led to a decrease of the elastic constant C11, as well as a slight decrease in the sample’s hardness, while the Young’s elastic modulus decrease was more noticeable. An intrinsic bulk property of PEEK is less radiation resistance than at its surface. The proportionality constant of Young’s modulus to indentation hardness for the pristine and irradiated samples were 0.039 and 0.038, respectively. In addition, a quasi-linear relationship between hardness and Young’s modulus was observed. The degradation of the polymer’s mechanical properties was attributed to electron irradiation-induced processes involving scission of macromolecular chains

Иcследование тонкой структуры Ti-Al покрытий на поверхности Ti, полученных методом механического сплавления

The work is devoted to the study of structural-phase transformations in composite coatings (Ti-Al)+Ti during mechanical alloying. The data on the structural-phase states of (Ti-Al)-Ti coatings after mechanical alloying have been obtained, confirming the mechanism of formation of the modified layer due to deformation compaction of powder particles on the titanium surface under mechanical action. As a result of mechanochemical fusion, a TiAl3 phase with a bcc lattice (I4=mmm structure) was detected, which corresponds to the stable state of the TiAl3 alloy. Under conditions of mechanical alloying of the structure, I4=mmm transforms into the L12 structure, which corresponds to the metastable state of TiAl3Работа посвящена исследованию структурно-фазовых превращений в композиционных покрытиях (Ti-Al)+Ti при механическом сплавлении. Получены данные о структурно- фазовых состояниях (Ti-Al)-Ti покрытий после механического сплавления, подтверждающие механизм формирования модифицированного слоя за счет деформационного уплотнения частиц порошка на поверхности титана под механическим воздействием. В результате механохимического сплавления обнаружена фаза TiAl3 с ОЦК-решеткой (структура I4=mmm), что соответствует стабильному состоянию сплава TiAl3. В условиях механического сплавления структура I4=mmm переходит в структуру L12, что соответствует метастабильному состоянию TiAl3