Mechanism for phase boundary sliding and its relevance to diffusion-solutio
n zone in SPD
n zone in SPD
(1. College of Mechanical and Electrical Engineering, University of Petroleum(Huadong), Dongying 257061, China;
2. Key Laboratory of Liquid Structure and Heredity of Materials,
Ministry of Education, Shandong University, Ji′nan 250061, China;
3. College of Resource and Environment Engineering,
East China University of Science and Technology, Shanghai 200237, China)
2. Key Laboratory of Liquid Structure and Heredity of Materials,
Ministry of Education, Shandong University, Ji′nan 250061, China;
3. College of Resource and Environment Engineering,
East China University of Science and Technology, Shanghai 200237, China)
Abstract: The diffusion behavior of Zn/Al interfaces in their powders sintering was investigated with SEM. The results show that Zn-Al eutectoid microstructure can be achieved through their powders sintering, and the diffusion characteristic between Zn and Al is just a demonstration of Kirkendall effect, by which Zn can dissolve into Al and contrarily Al cannot dissolve into Zn. During sintering, a diffusion-solution zone /′ has formed and subsequently transforms into eutectoid microstructure in cooling process. The superplastic deformation mechanism of Zn-Al eutectic alloy is phase boundary sliding which is controlled by diffusion-solution zone α′. If diffusion-solution zone α′ is unsaturated, it will have much more crystal defects and the combination between α′ and β phase is weak, thus the process of phase boundary sliding becomes easily; on the contrary, if the diffusion-solution zone α′ becomes thick and saturated, the sliding will be difficult.
Key words: Zn-Al alloy; superplasticity; phase boundary sliding; diffusion-solution zone(DSZ)