Substitution by Ubiquitously Alloying Elements for α+βType Ti-6Al-4V and Characteristics of Their Levitation-Melted Alloys

Abstract

Ti 5.5Al 2Fe alloy has been theoretically designed by modification of Ti 6Al 4V alloy, using ubiquitously alloying elements in order to establish the strategic method for suppressing utilization of rare metals. The utilization of the cold crucible levitation melting (CCLM) is very useful, because titanium is very chemically reactive at high temperature. The experimental alloys with high purity and without contaminations from a crucible were prepared, and the homogeneous melt was also achieved by the diffusion mixing effect of CCLM. The microstructure, phase stability, strength, corrosion resistance and workable properties of the designed alloy, were comparable to those of Ti 6Al 4V. The alloy design can be successfully carried out even using ubiquitously alloying elements by the d electrons concept, which leads to the establishment of one method for the strategic utilization of rare metals.

Alloy Design of Ti Alloys Using Ubiquitous Alloying Elements and Characteristics of Their Levitation-Melted Alloys

“…It is important for the strategy of titanium alloys that high performance alloys are developed using ubiquitous elements such as iron, aluminum and interstitial ones, etc. [4][5][6] However, in most cases methods for the development are largely dependent on the trial-and-error experiments and some empirical rules. Therefore, the development is so inefficient and also expensive.…”

Effect of Si and Ge Addition on the Evolution of Microstructure in Near Alpha Titanium Alloy

“…In order to achieve better fuel economy, there is a major focus to increase the operating temperature of these components. Addition of small amount of silicon has been found to significantly improve creep resistance [2][3][4][5][6][7]. Highly stable grain boundary precipitates could reduce the grain boundary sliding and uniform precipitation could restrict the dislocation creep at high temperature.…”