Of uniform standards and methods of evaluation of aerospace titanium castings retardant properties

Of uniform standards and methods of evaluation of titanium flame retardant properties. Properly evaluate flame retardant properties of titanium alloys is one of the key technologies of flame Titanium precision castings  titanium alloys, including combustion simulation methods and testing techniques. Currently, the evaluation method on the flame retardancy is no uniform standard, countries have adopted different methods of testing. So retardant performance evaluation method to develop a unified standard titanium will effectively promote the exchange of national retardant titanium. (2) improve the overall mechanical properties of Titanium precision castings retardant. Compared with flame titanium, titanium alloy retardant poor mechanical properties, the working temperature is lower. On how to further improve the mechanical properties of the(3) reduce the flame titanium costs. Resistant Titanium alloy sheets contains a lot of noble metal elements V, resulting in higher costs, limiting its applications. Domestic scholars have adopted partial substitution of lower-priced Mo V for a certain amount of research to try. alloy of the need for a deeper study.

Modern superplastic deformation theory that grain boundary sliding is the main way of superplastic deformation

Modern superplastic deformation theory that grain boundary sliding is the main way of superplastic deformation, diffusion and dislocation motion inside the grain and the grain boundary is the main coordinating mechanism of grain boundary sliding. Superplastic forming of titanium alloy pump  B-phase diffusion creep or dislocation creep dominated: A phase to the grain boundary sliding-based, coordinated jointly by diffusion and bit dislocation motion; A and B are two phases flow to A and B phase boundary migration to complete. Hydrogen in the titanium alloy superplastic forming :( mainly plays a role in the following) was added to increase the diffusivity of hydrogen in the alloy elements, resulting in enhanced B-phase diffusion slip A creep and titanium casting process intergranular phase. (2) the diffusion of hydrogen activated dislocation pinning promote the climb and slide dislocations, improved sliding capacity of B grains, the coordinating role of dislocations in favor of A / A grain boundary sliding requested. (3) hydrogen-induced weak bond effect, reducing the diffusion activation energy, enhanced atomic diffusion capacity, improve the superplastic flow capacity. (4) the Titanium alloy valve addition of hydrogen significantly reduces B \ A + B transition temperature, increase the volume fraction of the B phase, a direct result of the increase and decrease the flow stress of the plastic, so that the titanium alloy can be deformed at a lower temperature and higher deformation rates were superplastic forming.

As the representative of the research and production facilities

As the representative of the United States Bureau of Mines research and production facilities for titanium investment casting technology in-depth research, development of the melting and casting process is suitable for titanium , which is a low-cost processing and forming of Titanium alloy valve opened up a new path. As a method of casting forming complex shapes can be directly manufactured parts eliminates a lot of the subsequent processing steps , thus increasing material utilization and reduce titanium alloy casting manufacturing costs.Titanium alloy valve in the aerospace engine usage and comparison of forgings , can be seen, Titanium alloy valve with clear growth trend will gradually reach the amount of titanium forgings for each equivalent level. In particular, the application of cast titanium valve in civilian areas , for example, if the casting can be mass produced with great golf club head , which promote the use and development of cast itanium alloy valve. In all system shell process parameters on shell quality and ultimately a greater impact on the quality of castings are: batter ingredients, namely powder -liquid ratio , dewaxing and roasting process parameters, this research labs now there are devices on the above parameters in-depth study and optimize selection.

With the memory titanium check valve deformation function at a particular temperature

With the memory alloy deformation function at a particular temperature , the temperature can produce a variety of devices, the temperature control circuit can be produced , thermostatic door , temperature of the pipe connection . People have made ​​use of Titanium alloy valve automatic memory alloy fire hydrant - fire temperature, memory alloy deformation, so that the titanium check valve opens, water spray fire. Making a connection to connect the mechanical parts , pipes , air refueling aircraft interface is the use of a shape memory alloy - two oil pipes tacking , the use of electric heating temperature change , the interface memory alloy deformation, so that the interface tight dripping titanium alloy does not leak . Making the area of ​​titanium check valve several hundred square meters of space station antenna from Fair - first made large parabolic antennas or planar , folded into a ball on the ground, with the spacecraft to the space , the temperature changes , since the development of a large area and the titanium check valve shape. Memory alloys have been to dozens of current development in the aerospace, military, industrial, agricultural , medical and other fields have a purpose , and the development titanium alloy pump trend is very impressive, it is grand plans for the titanium check valve benefit of mankind.Application memory alloy application memory alloy is widely used. For example, the fastening pin machinery, fittings, fire alarm on electronic equipment , connectors , integrated circuits, soldering.