Effects of Cr and Mo Contents on Sintering Mechanisms of Mo₂FeB₂ Base Hard Alloys

Abstract

The liquid phase sintering of Fe-6 wt%B-(38-53) wt%Mo-(0-10) wt%Cr alloys is studied by means of DTA, dilatometric measurements and microstructural observations. In addition, the mechanical properties of the sintered alloys are discussed. The results can be summarized as follows.
(1) With the increase of the Cr content, the temperature ranges of L₁ and L₂ reactions, γ-Fe+Fe₂B→L₁ and γ-Fe+Mo₂FeB₂→L₂, shift to higher temperature.
(2) As the Mo content increases, the temperature ranges of the L₁ and the L₂ reactions rise up when the Cr content is fixed.
(3) The Cr distributes uniformly in Mo₂FeB₂, in the hard phases containing a small amount of Fe₂B and in a ferrous binder.
(4) Transverse-rupture strength values around 2.0 GPa are obtained for the Cr content up to 5 wt%.