Silicon nitride(Si3N4)based ceramics are one of the most attractive advanced engineering materials,which have been widely used under high-speed rotational operation or for mechanical contacts across a curved surface.In the present study,rotationally symmetric texturing of Si3N4,with radial grain align-ment,was obtained by centripetal sinter-forging(CSF)of a partially sintered sample.The average values of the included angles between the c-axis of the local Si3N4 grain and radial direction were approxi-mately 16.4° and 11.0°,on the section plane perpendicular to the pressing direction,and parallel to both the pressing and radial directions,respectively.The compressive strain in the pressing direction forced the ceramic body to flow towards the central axis,resulting in compressive strain in the tangential di-rection and tensile strain in the radial direction.A fundamental physical model was created to simulate the grain rotation during the 3-dimentional strain reorientation,which revealed the rod-like grain would preferentially rotate toward the center of the sample under the CSF process.In addition,due to the fric-tion between the sample surface and the pressing punch,the increased shear strain could enhance the Si3N4 grain alignment.Consequently,ceramics with rod-like grains perpendicular to the curved side sur-face could be anticipated by applying the centripetal forming concept in a controlled manner.

Da-Wang Tan;Zhen-Yong Lao;Wei-Ming Guo;Akira Kondo;Takahiro Kozawa;Makio Naito;Kevin Plucknett;Hua-Tay Lin

Department of Electromechanical Engineering,Guangdong University of Technology,Guangzhou 510006,China;Joining and Welding Research Institute,Osaka University,11-1 Mihogaoka,Ibaraki,Osaka 567-0047,Japan;Department of Mechanical Engineering,Dalhousie University,Halifax,Nova Scotia B3H 4R2,Canada

材料科学技术（英文版）

[1]Da-Wang Tan;Zhen-Yong Lao;Wei-Ming Guo;Akira Kondo;Takahiro Kozawa;Makio Naito;Kevin Plucknett;Hua-Tay Lin-.Fabrication and modelling of Si3N4 ceramics with radial grain alignment generated through centripetal sinter-forging)[J].材料科学技术（英文版）,2022(31):1-14

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