Abstract: Composite materials are provided based on titanium diboride and processes for their preparation.The composite materials contain(1) 70 to 98% by volume of titanium diboride,(2) 1 to 15% by volume of Fe.sub.2 B and(3) 1 to 15% by volume of Ti.sub.2 O.sub.3and have the following properties:density at least 93% of the theoretically possible density of the total composite material,hardness (HV10) greater than 1,900,bending fracture strength (measured by the three-point method at room temperature) at least 400 MPa andfracture resistance K.sub.IC (measured with a sharp incipient crack produced by the bridge method) of at least 4.5 MPa.sqroot.m.

Abstract: A process for the powder metallurgical production of structural parts of high strength and hardness from silicon-manganese or silicon-manganese-carbon alloyed steels. The alloying elements Si and Mn or Si, Mn and C are mixed, in powder form, by way of the alloy carriers ferrosilicon, ferromanganese or a silicon-manganese-iron master alloy containing silicon and manganese in the ranges from 10 to 30 weight percent Si, 20 to 70 weight percent Mn, remainder Fe, with an iron powder and when carbon is present with graphite, to form a powder mixture. The powder mixture is compressed and sintered at a temperature in a range from 1150.degree. C. to 1250.degree. C. and then cooled.