Experimental investigation of eutectic point in Al-rich Al-La,Al-Ce,Al-Pr and Al-Nd systems

In order to confirm the eutectic composition, eutectic temperature and phases of Al-rich Al-RE(La, Ce, Pr, Nd) binary systems, the eutectic Al-RE alloys with the controversial compositions were investigated. The scanning electron microscopy/energy dispersive spectroscopy(SEM/EDS), differential scanning calorimetric(DSC) and cooling curve tests analysis indicated that a similar eutectic composition(~12 wt.% RE) on the Al-rich region was observed in the Al-La, Al-Ce, Al-Pr and Al-Nd alloys, and the eutectic structure of the alloys was consisted of α-Al and α-Al11RE3 phases by combining with X-ray diffraction(XRD) tests. In addition, the eutectic temperatures determined by DSC and cooling curve tests were very close and around 645 oC.     

Modifications of iron and manganese on the melt equilibria of binary systems – a critical assessment

To determine the influences of modifications of an element on the melt equilibria of binary systems, quite specific requirements have to be met in relation to the configuration of the stable and unstable equilibria lines, and these are indicated at the onset. In relation to modifications of iron, they enable clear conclusions to be drawn as to their influences, and enable critical assessment of the influence of the manganese modifications on the melt equilibria, regarded as dubious, in the systems Fe-Mn and Mn-Si, and also in manganese-rich Mn-X systems with X = Pd, Ta, Rh, In, Sb, Ru, Cu. They also enable absent or incorrectly drawn stable and unstable melt and transformation equilibria of the systems Fe-Mn and Mn-Si to be effectively supplemented. A critical thermodynamic assessment of the measured manganese vapour pressure curves provides important indications as to the stable and unstable melt and transformation equilibria of the manganese modifications.     

二元互不溶体系合金机械合金化的热力学研究进展

二元互不溶体系合金在机械合金化的非平衡态过程中能够形成过饱和固溶体、非晶和纳米相复合结构等亚稳相,并表现出与其微米尺度结构合金所不同的性能。综述了Alonso热力学模型和机械合金化在二元互不溶体系合金中制备亚稳相的热力学计算。     

Some factors determining the type of phase diagram in binary systems formed by refractory oxides

Summary From literature data on the investigation of binary oxide systems an approximate correlation has been established between the ionic radii and electronegativities on the one hand and the type of phase diagram on the other. The conditions in which systems are formed with a eutectic structure of the liquidus—solidus region, or with solid solutions or chemical compounds, were determined in advance. Hitherto uninvestigated binary systems formed by oxides of rare earth elements, yttrium and scandium with oxides of group II elements (beryllium, calcium, magnesium, strontium, and barium) were analyzed.