Influence of the Transition Metals on Structure and Mechanical Properties of Titanium-Base Alloys

Abstract

Titanium belongs to a number of transition metals with an unfilled d-shell. Because of this peculiarity of electron structure, in the course of interaction with transition metals of IV—VIII groups, as well as with metals of I group of the Periodic Table, titanium forms phase diagrams with a regularly changing shape. With the increase of the alloying component group number they change from ones with full mutual solubility for both modifications of titanium to ones with eutectoid decomposition. With sufficiently high cooling rates the character of phase transformations and the alloy structure types are determined by the metastable phase diagram. However, with an increasing alloying component group number the part played by the equilibrium phase diagram in alloys increases. The rate of eutectoid decomposition grows and this leads to peculiarities in the phase transformations in quenched titanium alloys. At present most experimental results on the phase composition and structure have been obtained for Ti—V, Ti—Nb, Ti—Cr, and Ti—Mo alloys. For the majority of other systems such information is in most cases fragmentary, while for alloys of titanium with metals of the platinum group there are practically no publications. With this in view, we set the task of conducting a systematic investigation of structure of alloys of titanium with metals of IV—VIII groups and to ascertain the effect of structure on the variation in hardness of these alloys.