Effect of change in Nb content on structure, phase composition and mechanical properties of alloys of Ti—xNb—1,25Si

  
G.Khomenko,
 
V.Puchkova,
 
T.P.Tereshchenko
 

I. M. Frantsevich Institute for Problems of Materials Science of the NAS of Ukraine, Omeliana Pritsaka str.,3, Kyiv, 03142, Ukraine
Electron Microscopy and Strength of Materials - Kiev: Frantsevich Institute for Problems of Materials Science NASU, 2015, #21
http://www.materials.kiev.ua/article/1729

Abstract

The structure, phase composition and mechanical properties of the alloy of Ti—xNb—1,25Si system (x = 16—30% wt.) depend on the content of alloying of Nb element and thermomechanical treatment methods (TTM): quenching at 950°C, forging at temperatures 900—950 °C followed by quenching in water, forging, followed by quenching and tempering at 560 °C, 4 hours were studied. It is shown that the alloys with Nb concentration of 16 to 20% are the most suitable by mechanical properties. We studied the structure, phase composition and determined strength and plastic characteristics as well the endurance limit and Young's modulus E. It is shown that the hardness of the alloys in the cast state are higher than hardened alloys. With increasing Nb content in the cast alloys the hardness slightly increases and only after 26% Nb reduces, and in the quenched alloys with increasing Nb content hardness slightly decreases and after 26% increases. It is found that the forging at a deformation of about 70% at 900—950 °C followed by quenching in water don`t provide a significant increase in strengthening of Ti—xNb—1,25Si alloys, and tempering of Ti—xNb—1,25Si alloys strengthens significantly but the plasticity is not increased. It is found that Young's modulus after quenching depending on the niobium content is in the range 63—70,5 GPa. Full text download


ALLOYING ELEMENTS OF NB AND SI, MICROHARDNESS, STRENGTH AND PLASTIC CHARACTERISTICS, THE PHASE-STRUCTURAL TRANSFORMATIONS, TINBSI ALLOY