REVIEW Review: liquid phase sintering Randall M. German Æ Pavan Suri Æ Seong Jin Park Received: 22 May 2008 / Accepted: 16 September 2008 / Published online: 11 December 2008 Ó Springer Science+Business Media, LLC 2008 Abstract Liquid phase sintering (LPS) is a process for forming high performance, multiple-phase components from powders. It involves sintering under conditions where solid grains coexist with a wetting liquid. Many variants of LPS are applied to a wide range of engineering materials. Example applications for this technology are found in automobile engine connecting rods and high-speed metal cutting inserts. Scientific advances in understanding LPS began in the 1950s. The resulting quantitative process models are now embedded in computer simulations to enable predictions of the sintered component dimensions, microstructure, and properties. However, there are remain- ing areas in need of research attention. This LPS review, based on over 2,500 publications, outlines what happens when mixed powders are heated to the LPS temperature, with a focus on the densification and microstructure evolu- tion events. Nomenclature A N C cos(u/2), dimensionless A SS Solid–solid contact area, m 2 (convenient units: lm 2 ) C Solid concentration in the matrix, m 3 /m 3 or dimensionless C G Grain connectivity, dimensionless C SS Contiguity, dimensionless D Particle size, m (convenient units: lm) D 1 First eigenvalue of diameter of curvature, m (convenient units: lm) D 2 Second eigenvalue of diameter of curvature, m (convenient units: lm) D S Temperature-dependent solid diffusivity in the liquid, m 2 /s F(G) Cumulative grain size distribution, dimensionless [0,1] F(L) Cumulative intercept size distribution, dimensionless [0,1] G Grain size, m (convenient units: lm) G 1 Bigger grain size, m (convenient units: lm) G 2 Smaller grain size, m (convenient units: lm) G 50 Median grain size, m (convenient units: lm) K 1 Mechanism dependent parameter for neck size ratio, m m /s (convenient units: lm m /s) K 2 Mechanism dependent parameter for sintering shrinkage, m m /s 2 (convenient units: lm m /s 2 ) K 3 Material constant in the densification rate calculation, m 3 /s (convenient units: lm 3 /s) K 4 Material constant in the grain growth rate calculation, typical units m 2 /s (convenient units: lm 2 /s) K 5 Material constant relating grain size to pinned microstructure, dimensionless L Intercept size, m (convenient units: lm) L 0 Initial length, m (convenient units: mm) L L Depth of liquid penetration, m (convenient units: lm) L 50 Median intercept size, m (convenient units: lm) R. M. German College of Engineering, San Diego State University, 5500 Campanile Drive, San Diego, CA 92812, USA P. Suri (&) Materials Technology Division, Heraeus Inc., 6165 W. Detroit Street, Chandler, AZ 85224, USA e-mail: [email protected] S. J. Park Center for Advanced Vehicular Systems, Mississippi State University, 200 Research Blvd., Starkville, MS 39759, USA 123 J Mater Sci (2009) 44:1–39 DOI 10.1007/s10853-008-3008-0
Review: liquid phase sintering
Jun 29, 2023
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