Effect of quenching temperature on the phase composition, structure and microhardness of the alloy Ti—18,7Nb—1,6Si

Abstract

The effect of heating temperature followed by quenching from a temperature of 1100— 1300 °C and reheating followed by quenching a temperature of 800 and 950 °C on the phase composition and distribution of the alloying elements Si and Nb, structure and microhardness of the cast alloy Ti—18,7Nb—1,6Si. It is found that increasing of the heating temperature for quenching lead to growth in grain size, the increase of solubility of Si in Ti with its redistribution in the material volume and sharp silicide dispersion at 1300 °C, and the decrease of the amount or grinding of ω phase. All of these factors lead to an increase of microhardness. Reheating and then quenched with 800 of 950 °C leads to a redistribution of Si, increase of the size of their silicides and redistribution in the material volume with precipitation them at the grain boundaries, increasing the size or amount of ω phases and significant decrease of microhardness. Full text download