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, existed in Al-Ni-Hf ternary system have been studied by means of X-ray diffraction method.Experimental values of cell parameters at different temperature were used to calculate the thermal expansion coefficients and their temperature dependences. It is shown that for intermetallic phase with cubic structure temperature dependence of thermal expansion coefficient is significantly different than for l one with tetragonal structure.Keywords: cell parameters, aluminum alloys, thermal expansion coefficient. IntroductionTernary Al-Ni-Hf alloys attract the attention as a perspective light materials, which can be strengthened by means formation of nanoparticles of intermetallics in albased matrix. These alloys reveal the concentration region of easy amorphyzation and can exist in amorphous state upon rapid cooling from liquid state. Therefore there are potential ability to form a different phases in order to improve the properties and first of all the mechanical ones.It is shown [1, 2] that solid-solution hardening of Ni 3 AI depends on the substitutional behavior of alloying elements, atomic radii difference and deviation from stoicheometry. It is also established that Hf additions a effectively improve a high-temperature properties and other important characteristics. In order to control the formation of intermetallic phases, strengthening Al-based alloys ternary phase diagram is needed. Unfortunately, such diagram is not completely investigated, especially for Al-rich region that motivates further investigation of alloys of this system. From published data follows that solubility of Hf in most stable intermetallics AlNi, AlNi 3 is about 5 and 10 % respectively.It is also shown that there are HfNi 2 Al and HfNiAl intermetallics in this system. Pseudobinary systems of binary and ternary compounds have been investigated be X-ray diffraction and physical properties measurements. As it is concluded in [3] pseudebinary eutectic reaction L ↔ NiAl + HfNi 2 Al takes place at 1350 °C, but no more publications, confining this reaction occurrence. Also the existence of two transition invariant reactions L + Ni 3 Al + Hf 2 Ni 7 and Al (Ni) + HfNi + Hf 2 Ni 5 have been reported to take place. Another invariant reactions are predicted but their existence should be confirmed in further investigations. Some calculations showed presence (Ni) + HfNi 5 +Hf 2 Ni 7 three phases field. Analyzing results on structure studies, physical properties measurements and calculated data one can see any contradiction between them that motivate further investigation of this ternary system. I. ExperimentalThe alloy was prepared from ingots of constituent elements (not less than 99.6 wt.%) by arc melting in a high-purity argon atmosphere. X-ray diffraction studies have been carried out by means of high temperature diffractometer, which allowed to investigate solid and liquid materials within temperature range from room temperature up to 1600 K. Sample was placed in vacuum chamber filled with pure helium in order to prevent oxidation of sample. Breg-B...

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Досліджено структурні зміни у разі нагріванні швидкозагартованих стопів системи Al-Fe-Nb (Al 90 Fe 7 Nb 3 і Al 93 Fe 4 Nb 3 ). За допомогою рентґенофазового аналізу підтверджено аморфну будову досліджуваних стопів, визначено її основні параметри та їхні зміни в інтервалі температур від 293 К до 893 К. Встановлено, що швидкозагартовані аморфні зразки у разі нагрівання кристалізуються у три стадії, які супроводжуються відповідними змінами фазового складу стопів та їхніх властивостей. Зокрема, встановлено, що зразки у аморфному стані володіють суттєво вищими значеннями мікротвердості, аніж їхні кристалічні аналоги.