Progress of solidification technologies and their applications in metal materials processing

The main tasks of solidification researches are to reveal the principles of phase selections, growth morphologies, solute redistribution and solidification defects in the process. Great achievements have been obtained in all of the above four aspects in the past decades, especially for binary alloys, which promoted the progress of materials processing engineering. Compared to 40 years ago, now the quality of castings and ingots can be much better controlled. Meanwhile, many new materials processing technologies have been developed based on solidification control, such as, rapid solidification, directional solidification, semi-solid processing, etc. The development of some new materials, such as metal matrix composites, metal glass, nano-crystalline materials etc. is also greatly benefited from solidification researches. The recent researches exploit the following important areas of solidification process: (1) the first area is to develop solidification theories for multi-component and multi-phase materials since most of the present theories are based on binary alloys up to nowj (2) the second interesting topic will be the studies on the microstructure of superheated and undercooled liquid metals and its influences on the solidification process, this may offer some new ideas for the solidification structure control and the development of advanced materials; (3) the applications of physical fields (electrical field, magnetic field etc.) and high energy beams (electronic beam, laser, plasma etc. ) in solidification process have become more and more popular. The related theories require detail researches. Key words : solidification principle! ; solidification technology.