Process for producing a high strength and high toughness sinter

A process for producing a high-strength and high toughness sinter comprising a crystal agglomerate which maintains a fibrous shape in the sinter and is composed of crystals of SiC and MC.sub.1-x wherein M is Ti and/or Zr and x is a number of 0 or more but less than 1, wherein sections of at least part of said crystal agglomerate maintaining the fibrous shape are deformed as will be able to most closely pack to fill up gaps which occur in said crystal agglomerate maintaining the fibrous shape, said process comprising

• laminating inorganic fibers composed of inorganic material (i), (ii), or (iii) defined below, to form a laminate,
• molding the laminate into a predetermined shape, and conducting heat-sintering simultaneously with the molding or after the molding in an atmosphere comprising at least one member selected from the group consisting of a vacuum, an inert gas, a reducing gas, and a hydrocarbon gas at a temperature of 1,700 to 2,200.degree. C.;
• (i) an amorphous substance consisting essentially of silicon, M, carbon, and oxygen,
• (ii) an agglomerate comprising fine crystalline grains each having a diameter of 500 .ANG. or less and essentially consisting of .beta.-SiC, MC, a solid solution composed of .beta.-SiC and MC and/or MC.sub.1-x wherein SiO.sub.y and MO.sub.z, wherein O<y, z.ltoreq.2, may be present around these fine crystalline grains, and
• (iii) a system comprising a mixture of said amorphous substance (i) with said agglomerate (ii);
• and
• wherein said inorganic fibers are woven into a plain weave.