Yong’an Zhang’s research while affiliated with General Research Institute for Nonferrous Metals (GRINM) and other places

The flow stress of spray formed 70Si30Al alloy was studied by hot compression on a Gleeble-1500 test machine. The experimental results indicated that the flow stress depends on the strain rate and the deformation temperature. The flow stress increases with an increase in strain rate at a given deformation temperature. The flow stress decreases with the deformation temperature increasing at a given strain rate. The relational expression among the flow stress, the strain rate, and the deformation temperature satisfies the Arrhenius equation. The deformation activation energy of 70Si30Al alloy during hot deformation is 866.27 kJ/mol from the Arrhenius equation.

Heat-resistant Al-Fe-V-Si aluminum alloys enhanced by in-situ TiC particles have been prepared by spray forming process with suitable process parameters. Research results show that the microstructure of the as-deposited alloy is fine and homogeneous. In-situ TiC particles prevent the unstable phases from coming into being. On the other hand, the TiC particles increase the volume fraction of heat-resistant phases. So the mechanical properties of the reinforced alloy by in-situ TiC particles are better than that of Al-Fe-V-Si alloy without the TiC particles. The hot extrusion temperature is also an important parameter to be considered. It is proved better to extrude the alloy at lower temperature. The tensile strength of the alloy without TiC particles is about 435 MPa at room temperature and is about 204 MPa at 350°C. However, when the alloy is enhanced by in-situ TiC particles, the strength of alloy is about 482 MPa at room temperature and is about 204 MPa at 350°C.

Heat-resistant Al-Fe-V-Si aluminum alloys enhanced by in-situ TiC particles have been prepared by spray forming process with suitable process parameters. Research results show that the microstructure of as-deposited alloy is fine and homogeneous. In-situ TiC particles prevent the unsteady phases from coming into being. On the other hand, the TiC particles increase the volume fraction of heat-resistant phases. So the mechanical properties of the enhanced alloy by in-situ TiC particles are better than that of Al-Fe-V-Si alloy without TiC particles. The hot extrusion temperature is also an important parameter to understand. Under the permission, it is better to extrude the alloy at lower temperature. The tensile strength of the alloy without TiC particles is about 435MPa at room temperature and is about 204MPa at 350°C. However, when the alloy is enhanced by in-situ TiC particles, the strength of alloy is about 482MPa at room temperature and is about 224MPa at 350°C temperature.

An ultra-high strength Al-11Zn-2.9Mg-1.7Cu alloy has been prepared by spray forming process. The microstructures of as-cast and as-deposited alloys have been studied. XRD analysis result shows that the phases of spray formed Al-11Zn-2.9Mg-1.7Cu alloy consist of a-Al, MgZn2, Al2Cu and Al2CuMg. T6 heat treatment process is used to strengthen the alloy. The ultimate tensile strength reach up to 810MPa, and the elongation is about 9~11%. This kind of aluminum alloy is an ideal structural material for the aerospace and automobile industries.

The pattern of making round billets by spray forming technology was studied by means of numerical method combined with experiment. The results show that during the atomization deposition process, the shape of the deposit reaches a stable state after a primary transient state, and then the round billet grows in the mode of equi-diameter. The basic condition to reach the stable state is that the withdraw velocity of the collector, ν, is smaller than a cosφ, where a is the atomization density along the atomization axis, and φ is the atomization angle. With the other technological parameters being constant, round billets with different diameters can be made by adjusting the withdraw velocity. Additionally, the ratio of gas flux to melt flux (G/M) also directly affects the shaping of round billets in the atomization deposition process.