Articles having improved resistance to thermal cracking

An indexable diamond-shaped cutting insert comprising:

• a cutting portion comprising a cemented carbide including a binder in which are dispersed hard particles of at least one of titanium carbide, chromium carbide, vanadium carbide, zirconium carbide, hafnium carbide, tantalum carbide, molybdenum carbide, niobium carbide, and tungsten carbide;
• a central hole;
• and
• a heat sink portion comprising a heat sink material having a thermal conductivity greater than a thermal conductivity of the cemented carbide, wherein the heat sink portion is in thermal communication with and is adapted to conduct heat from the cutting portion.

A cutting tool comprising:

• a cutting portion comprising
• a first region comprising a first cemented carbide including a binder in which are dispersed hard particles of at least one of titanium carbide, chromium carbide, vanadium carbide, zirconium carbide, hafnium carbide, tantalum carbide, molybdenum carbide, niobium carbide, and tungsten carbide, and
• a second region comprising a second cemented carbide including a binder in which are dispersed hard particles of at least one of titanium carbide, chromium carbide, vanadium carbide, zirconium carbide, hafnium carbide, tantalum carbide, molybdenum carbide, niobium carbide, and tungsten carbide;
• and
• a heat sink portion interposed between the first region and second region, wherein the heat sink portion comprises a heat sink material having a thermal conductivity greater than a thermal conductivity of the first and second cemented carbide;
• and wherein the heat sink portion is adapted to conduct heat from the cutting portion.