Comparison table of titanium alloys by country

Aluminium alloying element. In order to maximise the solid solution strengthening effect of aluminium and to avoid embrittlement of the alloy due to excess Al, the alloying of high temperature titanium alloys should follow the equivalent empirical formula proposed by ROSENBERG, which ensures that the alloys are thermally stable while increasing the heat-resistant strength. α The elements in titanium alloys are stabilised by inhibiting the phase transition at the phase transition temperature or by increasing the phase transition temperature. These elements in α Titanium alloys stabilise by inhibiting or increasing the phase transition temperature. Compared to β-type titanium alloys, α-type alloys have good creep resistance, strength, weldability and toughness, making them the alloys of choice for use at high temperatures. At the same time, α-type alloys do not have cold embrittlement, it is also suitable for use in low temperature environments, expanding its scope of application. α-type alloys have poor forging, easy to produce forging defects, can be reduced by reducing the rate of machining per pass and frequent heat treatment to control the forging defects. α matrix is a stable phase, for a given composition of the alloy, the change in its properties is mainly the change in the size of the grains, because the yield strength and creep strength are related to the grain size, grain size, stored during deformation, and the change of the grain size of the alloy. α-type titanium alloys can not be heat-treated to improve strength, annealed strength basically no change or little change. Some alloys contain high amounts of Al, Sn, Zr and small amounts of β-stabilising elements (generally less than 2%). Although these alloys contain β-phase, the matrix is mainly composed of α-phase, and they are very close to α-type alloys in terms of heat treatment sensitivity and processing properties, and are called near-α-type titanium alloys. Near-alpha alloys were developed on the basis of the realisation that high creep strength could be obtained by strengthening the α matrix with solid solution alloying elements. Most near-alpha alloys are now an important alloy type for high temperature titanium alloys because of their good thermal stability. Its strengthening mechanism is the fast diffusion of atoms in the β-phase, which makes it easy to creep, and the β-stabilising element also inhibits the embrittlement of the α-phase (i.e., it slows down the formation of ordered phases in the α-phase).

Common α-type titanium alloys (including near-α-type alloys) are Ti811 (Ti-8Al-1Mo-1V), Ti-6Al-2Zr-1Mo-1V, Ti-679 (Ti-2.25Al-11Sn-5Zr-1Mo-0.25Si), BT18 (Ti-7.7Al-11Zr-0.6Mo-1Nb-0.3Si), and Ti6242S (Ti-6242S). and Ti6242S (Ti-6Al-2Sn-4Zr-2Mo-0.1Si), etc. Their compositions and properties are listed in Table 2.