Abstract

In this work, the isothermal section of the Al-Ca-Zn system has been investigated at 350°C using 5 diffusion couples and 26 key alloys. The actual compositions of the alloys are measured by inductively coupled plasma technique. Phase relations and solubility limits of the binary and ternary compounds have been determined by means of electron probe microanalysis and X-ray diffraction. In the current work, five ternary compounds have been found, three of which are reported for the first time: ternary intermetallic IM1 with the formula AlxCa8.5Zny (26≤x≤29, 62≤y≤65 at 350ºC), ternary intermetallic IM3 with the formula Al3-xCaZx (2≤x≤2.2 at 350oC) and ternary intermetallic IM5 with the formula Al2Ca9Zn3. The crystal structure information of IM1 has been studied by X-ray diffraction technique. XRD data has shown that IM1 is a solid solution that crystallizes in a cubic structure with Pm3 ̅m (221) space group having BaHg11 prototype. The homogeneity ranges of IM2 and IM4 have been determined at 350oC. Binary compounds Al14Ca13, Al2Ca, Al4Ca, CaZn2, CaZn3, CaZn5, CaZn11 and CaZn13 have extended solid solubility into the ternary system. For Al14Ca13, Al2Ca and Al4Ca, Al-atom is substituted by Zn. For CaZn2, CaZn3, CaZn5, CaZn11 and CaZn13 Zn is substituted by Al.