Zhenqing Wang

Microstructures and grain refinement performance of rapidly solidified Al–Ti–C master alloys

Abstract In the present work, the microstructures and grain refining performance of melt-spun Al–3.5Ti–0.15C, Al–5Ti–0.3C and Al–10Ti–1C (in wt.%) alloys have been investigated, using X-ray diffraction (XRD), scanning electron microscopy (SEM), and grain refining tests. All three types of ingot-like alloys contain coarse slablike TiAl 3 and fine TiC particles. The microstructures of melt-spun Al–3.5Ti–0.15C and Al–5Ti–0.3C alloys are composed of spherical or near-spherical dispersed TiC particles and α-Al supersaturated solid solution, while melt-spun Al–10Ti–1C alloy consists of small blocky TiAl 3 , spherical or near-spherical TiC particles and α-Al solid solution. Furthermore, most of the TiAl 3 and TiC particles are distributed in the edge zone of the chill surface of the rapidly solidified alloy ribbons. Rapid solidification process (RSP) does not improve the grain refinement performance of Al–Ti–C master alloys. The reasons for the formation of microstructures and the grain refining performance of melt-spun Al–Ti–C master alloys have also been discussed.

TEM observations of a rapidly solidified Al–Ti–C alloy

Abstract In the present work, the microstructural characterization of a melt-spun Al–20 Sb alloy has been carried out using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The phases present in the melt-spun Al–20 Sb alloy were determined to be α-Al and AlSb, identical to those in the ingot-cast alloy. The microstructure of the melt-spun Al–20 Sb alloy is dominantly composed of primary AlSb dendrites embedded in the α-Al matrix, different from that of the ingot-cast alloy composed of primary AlSb plates within an α-Al/AlSb eutectic matrix. In addition, some areas comprise primary AlSb particles within the α-Al matrix in the melt-spun alloy.

Refractive index and absorption of lead bromide crystals

Abstract Lead bromide (PbBr2) crystals in [001] orientation were obtained by the Bridgman growth method. The orientation of the principal refractive axes of the crystals was determined, and their principal refractive indices were measured by the least deviation angle at eight selected wavelengths. The optical axial angle and the dispersion of refractive index in the visible spectral range were calculated by Sellmeier’s formula. Optical transmission and reflection spectra were measured and the absorption coefficient α was determined. Using the calculated α(hν) dependence, the bandgap width corresponding to indirect transition was determined.

Erratum to: Erratum

[This corrects the article on p. S10 in vol. 3, PMID: 21673847.][This corrects the article on p. S17 in vol. 3, PMID: 21673848.].