Abstract The present invention relates to a ceramic whisker-containing cutting insert for chipforming machining of steel having improved mechanical, thermal and wearing properties. Besides an oxide-based matrix, the material contains 5-50, preferably 10-40, % by volume of homogeneously distributed whiskers or platelets of nitrides, carbides and/or borides of metals from group IVB (Ti, Zr or Hf) and/or VB (V, Nb or Ta) in the periodic system (or solid solutions thereof) having a linear expansion coefficient being lower than that of Al2O3, preferably at the most 85% of that for Al2O3 measured at 300-1300K. The properties of the composite material can be further modified by coating the whisker material with thin layers. The whisker reinforced cutting tool material shows an improved toughness behavior.
Oxide-based ceramic cutting insert for chipforming machining of steel, comprising a ceramic oxide-based matrix of alumina and less than 20% zirconia and 5-50% by volume, of homogeneously dispersed whiskers or platelets of at least one of the carbides of in the periodic system Nb, Hf and V and the nitride of Hf, the whiskers or platelets having a linear expansion coefficient measured at 300-1300K which is at the most 85% of that of Al 2 O 3 .
Claim 2
Dependent Claim
78 words
Oxide-based ceramic cutting insert for chipforming machining of steel, comprising a ceramic oxide-based matrix of alumina and less than 20% zirconia and 5-50% by volume, of homogeneously dispersed whiskers or platelets of at least one of the carbides of in the periodic system Nb, Hf and V and the nitride of Hf, the whiskers or platelets having a linear expansion coefficient measured at 300-1300K which is at the most 85% of that of Al 2 O 3 .
Claim 3
Dependent Claim
20 words
Cutting insert according to claim 1, wherein the oxide-based matrix contains 10-40% by volume of the said whiskers or platelets.
Claim 4
Dependent Claim
33 words
Cutting insert according to claim 1, wherein the whiskers or platelets have a linear expansion coefficient measured at 300-1300K, which is at the most 70% of that of Al 2 O 3 .
Claim 5
Dependent Claim
20 words
Cutting insert according to claim 1, wherein the oxide-based matrix contains 25-35% by volume of the said whiskers of platelets.
Claim 6
Dependent Claim
16 words
Cutting insert according to claim 1, wherein the whiskers or platelets are HfC, HfN, or NbC.