Brazing Alloy is the simplest and most reliable connection between titanium and titanium alloys and other metals, and can also be used for the connection of miniature complex parts of titanium and titanium alloys. Brazing Alloy is an essential material for brazing, usually divided into two categories according to its melting temperature range: Gallium, bismuth, tin, lead, cadmium, zinc, etc., and titanium and its alloys are rarely brazed with soft brazing material. The liquid phase line temperature is higher than 450 °c is called the hard filler. Mainly include: aluminum base, magnesium base, copper base, silver, magnesium base, Kim, titanium base, etc., currently for titanium and titanium alloy brazing, the application of the more common silver base, aluminum and titanium base three categories. The copper base solder is generally unsuitable for the formation of brittle intermetallic compounds.
Because of the high temperature activity of titanium, Brazing Alloy is generally carried out under the protection of vacuum or argon gas. Titanium is easily alloyed with brazing, so it is easy to solder. But Brazing Alloy should be easy to form metal compounds, causing joint brittleness, for this reason should choose suitable solder or reduce brazing temperature, shorten brazing time so as not to form brittle intermetallic compounds.
The alloy of α-titanium alloy K-Beta near 0 is alpha-titanium, which contains almost no beta-stable elements.
This kind of alloy can not be strengthened by heat treatment, the main advantage is organization stability, corrosion resistance, easy welding. The disadvantage is low strength, poor pressure processing. The use temperature of industrial pure titanium can reach 250, and the TA7 temperature can reach 450 Shan.
The alloys near α-ti-K-β Boo 23 generally belong to nearly α-ti alloys.
Because the atom diffusion coefficient is large in β phase, the atom diffuses rapidly and the creep is easy to occur. In order to improve creep resistance, Brazing Alloy is necessary to reduce the beta phase in (α + β) titanium alloy, so the so-called near-α titanium alloy is developed, and the content of β-stabilized elements in this kind of titanium alloy is generally less than 2%.
(α + Beta) titanium alloy
K-β F.23 titanium alloys generally belong to α + β titanium alloys, also called two-phase titanium alloy. The aluminum equivalent in this kind of titanium alloys is generally controlled under 8%, and the additive amount of β-stabilized elements is 2 10, mainly for the purpose of obtaining a sufficient number of beta phases to further improve the pressure-processing and heat-treatment strengthening capability of titanium alloys.
The alpha phase of a large number of six square lattices is a good guarantee of high temperature properties, low temperature properties and good solderability. and a certain amount of β-phase is the alloy has a good process plasticity and heat-treatment of the guarantee.
The aluminum equivalent of low aluminum alloy is less than 6%. Such titanium alloys generally contain more beta-stable elements, β-phase number and stable degree of β-phase in the microstructure of $number, the number of β-phase after quenching can reach 55%, this kind of titanium alloy with medium strength, plasticity, creep resistance and thermal stability, the use of temperature in the 300 range.
Aluminum equivalent Two-phase titanium alloy with high aluminum is greater than or equal to 6%. In addition to containing more aluminum, tin, zirconium and the right amount of β-stable elements, especially molybdenum and vanadium, some alloys also added micro-silicon, is currently in the $number range of the most widely used titanium alloy.
Beta-type Titanium alloy
K-β Sian titanium alloys are generally β-type
K-β-1 titanium alloys are near beta-type titanium alloy. Sometimes called transition (α + β) titanium alloy, this alloy annealing state is α + beta two-phase, so sometimes referred to as the excessive α + β alloy, can be treated by two-phase titanium alloy. However, in quenching, beta phase can be retained from high temperature to room temperature, or ω phase change, so that all the microstructure of the quenching state of the metastable beta or metastable beta + ω phase. Therefore, it is classified in β alloy.
The β-ti-alloy of K-β 1 5 is a metastable β alloy, and the equilibrium state of the alloy is still α + β, beta phase content of more than 50%, but under the general annealing cold speed, beta can be retained to room temperature, so that all of the microstructure in the annealing state of the beta phase, of course, metastable beta alloy β-phase stability is higher than the near-beta alloy.