[en] Higher strength and lower ductility have been observed in the prestrained and aged Ti-10Mo-8V-1Fe-3.5Al (TB3) alloy. In order to improve the ductility of prestrained TB3, two-step aging treatment was introduced. Tensile tests showed that the elongation of prestrained samples was increased to the same level of the unstrained and peak-aged ones without decrease in strength by the two-step aging. Transmission electron microscopic (TEM) examinations revealed that dislocations introduced by prestrain were almost eliminated by the two-step aging treatment, which was proposed to be the main cause for the ductility recovery. In addition, in the prestrained and aged TB3 samples, parallel α plates of one variant were generally observed under TEM.

[en] K-shell X-ray spectra of Al were measured by the interaction of 600-3400 keV Xe^q+ (q = 12-29) ions with Al surface. The X-ray yields per incident ion were deduced and the K-shell ionization cross-sections were obtained from the experimental yield data. With the same incident energy, the K-shell ionization cross-sections of Al excited by Xe^q+ (q < 26) ions were of the same order of magnitude, while for q = 26 and 29 Xe ion collisions, they were, respectively, about two and ten times larger. Taking into account the binding-energy-modification and the recoil effect of target atoms, the binary encounter approximation (BEA) theory was consistent with the experimental data for q < 26 Xe ion collisions, but it underestimated those excited by q 26 and 29 Xe ions. This indicates that the K-shell ionization of target induced by Xe^q+(q < 26) ions was mainly due to the direct Coulomb excitation. However for q = 26 and 29 Xe ions collisions, the transfer of 3d vacancies of projectile to the 1s orbital of target via rotational coupling of the 3dπ, δ-3dσ molecular orbitals, which were formed in the ion-atom quasi-molecule, may cause a considerable contribution to the enhancement of ionization. In addition to the well known Auger and X-ray transition, our experiments proved that the molecular orbital transition ('side-feeding') mechanism is also a significant channel for de-excitation of hollow atoms formed below the surface. (authors)

[en] The visible light emissions from the sputtered Al species and the neutralized projectiles during Kr¹³⁺ ions bombarding the Al surface have been measured in the wavelength range of 300–600 nm. The three spectral lines belonging to transitions of Al I 3p ²P_3/2^o–3d ²D_5/2 at 309.0, Al II 3d ³D₁–4f ²F₂^o at 358.5 and Al I 3p ²P_3/2^o–4s ²S_1/2 at 396.1 nm have been observed, as well as five spectral lines from the incident ion attributing to transitions of Kr I 5s ²[3/2]₁^o–5p ²[1/2]₁ at 587.9, Kr II 4d ⁴D_1/2–5p ²S_1/2 at 485.8, Kr II 4d ³D₂^o–5p ³D₃ at 434.3, Kr II 5s ²P_3/2–5p ⁴S_3/2^o at 430.1 and Kr II 5s ⁴P_1/2–5p ²D_3/2^o at 409.9 nm

[en] Research highlights: → Stress-aged metastable β titanium alloy samples was prepared. → Variant selection effect was observed in these stress-aged samples. → Stress-aged samples were toughened in comparison with conventionally aged ones. - Abstract: A kind of metastable beta titanium alloy, i.e. Ti-10Mo-8V-1Fe-3.5Al, was aged under elastic compressive stress. Transmission electron microscopy (TEM) investigations revealed that, in the stress-aged samples, precipitated alpha plates were parallel to each other. However, in the conventionally aged samples, alpha plates intersected each other. In other words, variant of alpha plate was selected in the stress-aged samples. Tensile tests showed that, at equivalent tensile strength, the stress-aged samples exhibited higher ductility, compared to the conventionally aged ones.