Microstructure Evolution Real-Time Observation of Compacted Aluminum Bulk Ceramics during Sintering Process
铝素坯烧结过程微结构演化的实时观测

In order to realize real-time observation of the sintering process for compacted metal powder bulk and accordingly verify existing theories,real-time and non-destructive observation of compacted aluminum bulk ceramics in sintering process was realized by synchrotron radiation x-ray computerized tomography(SR-CT) technique.3-D reconstructed images describing ceramic body interior microstructure evolution during the whole sintering process were obtained based on filtered back projection algorithm and digital image processing technology.Microstructure evolution of the specimen during solid-state sintering process is as follows: in the early and middle stages(Sintering time t<180 min,Temperature T<600℃) the sintering neck is formed and growing with sintering time;when from middle stage into later stage(Sintering time t≥ 180min,Temperature T≥600℃),the sample’s internal structure evolution increased,the former interconnected pores become isolated.There is a linear relationship between sintering neck size and time logarithm.Middle stage and later stage can be recognized based on the curve characteristics.Densification characteristics of the sample in different sintering stages were analyzed,and linear relationship between porosity and time logarithm in the middle stage of sintering was obtained.Results verify the existing sintering theory,and provide high quality experimental data for further improving the sintering theory and establishing diffusion and constitution model.