Strength and deformation behavior of bulky cementite synthesized by mechanical milling and plasma-sintering

Deformation behavior of bulky cementite was investigated by compression, bending and tension tests at various temperatures and strain rates. Specimens of cementite {(Fe0.95Mn0.05)75C25} were prepared by plasma-sintering from a mixture of mechanically milled Fe, Mn and graphite powders. The maximum compressive strength observed was 3.2 GPa at 573 K. At room temperature, specimens exhibited brittle fracture under compression where the fracture strength was between 2 and 3 GPa. At elevated temperatures under all types of loading modes, specimens showed high ductility, where grain boundary sliding was the dominant deformation mechanism because of the favorable grain size for superplasticity (less than 1.0 μm).