Spray forming is used in high pressure inert gas into small droplets alloy droplet atomized, flight and cooling in the high wind, in a process not fully solidified deposited into the blank. It is the material of fine and uniform microstructure, the various advantages of rapid solidification technology can inhibit themacrosegregation, also has from the alloy smelting tonear net forming step to complete the advantage,therefore attach great importance to the people.
Aluminum alloy has the advantages of low density, high strength, good toughness and corrosion resistance, in the aerospace industry is widely used as a structural material, at the same time, is also being activelydeveloped as advanced materials used in high-grade carand car engine.
Casting process is the main business of traditional aluminum alloy preparation method, but has been difficult to meet the need for the preparation of high performancealuminum alloy. First, the traditional process has been difficult to further increase the strength, ductility, rigidity,heat resistance and corrosion resistance; second, in the pursuit of high performance, casting cost due toequipment and finished product rate decreased rapidlyrise; third, the alloy content increased, plastic tends to decrease, thus the subsequent pressure processing costrise, yield reduction. Therefore, the high cost of production greatly improve the advanced aluminum alloyusing threshold, seriously affecting the overall marketsize. In these respects, spray forming process has thedouble advantage is performance and cost, can make theadvanced aluminum alloy used to lower the threshold,can further improve the performance, in the certain scopewith aluminum and steel, which quickly cultivate advancedaluminum alloy market, and turn to promote access toscale cost advantages of spray forming process.Therefore, spray forming process will become the mainadvanced production technology of aluminum alloy.
The success of spray forming of high performance aluminum alloy material basically has the following kinds:
(1) high strength aluminum alloy. As Al Zn ultra high strength aluminum alloy. The solidification range of Al - Zn alloy with wide, specific gravity difference is big,produced by traditional casting method, easy to producethe macro segregation and hot cracking tendency. Rapid solidification characteristics of spray forming technologycan solve this problem very well. In the developed countries has been applied in aerospace vehicle parts and automobile engine connecting rod, shaft supportingseat and other key components.
(2) strong, high specific modulus of aluminum alloy is higher than that of. Al-Li alloy has small density, highelastic modulus, is a promising structural materials foraerospace. Give full play to the role of ingot metallurgymethod limits the performance potential of Al-Li alloy in a certain extent. Injection forming rapid solidification technology for Al-Li alloy has opened up a new way.
(3) low expansion, wear resistant aluminum alloy. Such as the hypereutectic Al - Si series high strength wear-resistant aluminum alloy. The alloy has low thermal expansion coefficient, good wear resistance and other advantages, but the traditional casting process, will form the coarse primary Si phase, leading to deterioration ofmaterial properties. Spray forming rapid solidificationcharacteristics effectively overcomes this problem. At present, the spray formed Al - Si alloy in developed countries has been made the car engine cylinder lineretc..
(4) the heat-resistant aluminum alloy. Such as Al - Fe - V - Si heat resistant aluminum alloy. The alloy has goodstrength and toughness at room temperature and high temperature, good corrosion resistance, can be in 150 ~ 300 ℃ even temperature range higher using partial substitution of titanium alloy, in the temperature range of work and heat resistant steel, in order to reduce weight,reduce the cost of. Spray forming process can at least through the process directly from liquid metal to producewith the rapid solidification characteristics, the density of the whole, the larger size of the blank, which can solve the problem of traditional craft.
(5) aluminum matrix composites. The spray formingtechnology and aluminum based composite material preparation technology together, developed a "sprayforming (Sprayco-deposiion) technology," is a good solution to the problem of particle reinforced segregation.