STRUCTURE AND PHYSICOMECHANICAL PROPERTIES OF EUTECTIC Ti-Si-X ALLOYS

摘要

We study the structure and physicomechanical properties of various eutectic alloys of Ti-Si-Zr, Ti-Si-B, and Ti-Si-Ga systems. It is shown that Ti-Si-Zr alloys with elevated concentrations of Zr reveal, due to the presence of (Ti, Zr)_2 Si dispersed silicides with sizes of about several hundred nanometers, improved mechanical properties as compared with the properties of alloys based on Ti_5 Si_3 silicides. The cast eutectic alloy of the Ti-Si-Zr-Sn system with a plasticity of approx 1.7percent is obtained for the first time. The formation of superfine eutectics based on the Ti_6Si_2B ternary compound in alloys of the Ti-Si-B system enables one to obtain titanium composites with improved refractory properties and elevated moduli of elasticity (of about 150GPa or, after additional alloying, as high as 165GPa). This can be promising for the development of new refractory titanium composite materials with elevated stiffness. The analysis of the combined effect of gallium and silicon in Ti-Si-Ga alloys reveals the possibility of getting titanium materials with high heat resistance, i.e., materials based on the (alpha-Ti(alpha_2-Ti_3Ga)+Ti_5 (Si, Ga)_3 binary eutectics.