Simultaneous Synthesis and Sintering of α‐Ti1–xAlx(N) (0 ≤x≤ 0.08) by a Self‐Propagating High‐Temperature Combustion Method

Abstract

Simultaneous synthesis and sintering of hexagonal α‐Ti1−x‐Alx(N) (0 ≤x≤ 0.08) solid solutions, which contain a small amount of nitrogen, have been performed by a self‐propagating high‐temperature combustion method under a nitrogen pressure of 4 MPa. Dense materials (∼99% of theoretical) prepared directly from a mixture of elemental (Ti and Al) powders reveal homogeneous microstructure composed of fine grains (12–16 μm). α‐Ti1−xAlx(N) (x= 0.02; Ti0.98Al0.02N0.26) exhibits a three‐point bending strength σb of 390 MPa, a Vickers hardness Hv of 9.24 GPa, and a fracture toughness KIC of 4.89 MPa·m1/2; their mechanical properties are much improved by doping Al into α‐Ti(N), in comparison with those (σb= 245 MPa, Hv= 9.02 GPa, and KIC= 3.77 MPa·m1/2) of α‐Ti(N) fabricated under the same conditions.