T15 is used for cutting tools that are exposed to extremely rigorous heat or abrasion in service. The M tool steels generally are considered to have molybdenum as the principal alloying element, although several contain an equal or a slightly greater amount of such elements as tungsten or cobalt.
Titanium aluminium nitride (TiAlN) or aluminium titanium nitride (AlTiN; for aluminium contents higher than 50%) is a group of metastable hard coatings consisting of nitrogen and the metallic elements aluminium and titanium. This compound as well as similar compounds(such as TiN and TiCN) are most notably used for coating machine tools such and endmills and drills to change their properties, such as increased thermal stability and/or wear resistance. Four important compositions (metal content 100 wt.%) are deposited in industrial scale by physical vapor deposition methods:
