Loading...

Effect of cobalt replacement by nickel on functionally graded cemented carbonitrides

Mohammadpour, M ; Sharif University of Technology | 2012

1419 Viewed
  1. Type of Document: Article
  2. DOI: 10.1016/j.ijrmhm.2011.07.001
  3. Publisher: 2012
  4. Abstract:
  5. Functionally graded cemented carbonitrides (FGCCs) are applied in cutting tools industry. Indexable inserts made from mentioned alloys have superior cutting performance and tool life thanks the formation of a surface modified layer with enhanced properties as well as crater wear resistance. Cemented carbonitrides are made of hard carbide/nitride/carbonitride particles that have been embedded in a metallic binder. Excellent wetting ability of tungsten carbide with cobalt has made this metal the first choice as binder. However, cobalt has high cost and environmental pollution impacts. Substitution of cobalt with other metals has always been figured out. Some other metals that have been used as binder are iron, nickel and manganese. In addition to lower cost, nickel has higher corrosion resistance than cobalt. In the present work, gradual substitution of cobalt with nickel in WC/2.5TiC0.7N 0.3/2.5TiC/0.2VC/8Co (numbers indicate wt.%) cemented carbonitride has been studied. This is supposed to make some alterations in mechanical and magnetic properties as well as formation of Cubic Free Layer. As sintered samples with different binder characteristics were prepared by powder metallurgy techniques and use of Hot Isostatic Pressure (HIP) and vacuum furnaces. Magnetic saturation, coercive force, Vickers hardness, and transverse rupture strength tests were carried out together with optical and scanning electron microscopy. Computational thermodynamics was applied to explain changes in magnetic properties of investigated alloys as well as plotting phase diagrams. Complete displacement of cobalt by nickel made an increase in transverse rupture strength (TRS) of final alloy by 37% with less than 6% decrease in Vickers hardness and doubled the thickness of Cubic Free Layer
  6. Keywords:
  7. Cemented carbonitride ; Computational thermodynamics ; Cutting tool ; Surface modification ; Cutting performance ; Environmental pollutions ; Free layers ; Functionally graded ; High costs ; Hot isostatic pressure ; Indexable inserts ; Lower cost ; Sintered samples ; Surface modified layer ; Tool life ; Transverse rupture strength ; Wetting ability ; Alloys ; Binders ; Carbon nitride ; Corrosion resistance ; Environmental impact ; Magnetic properties ; Manganese ; Metal working tools ; Nickel ; Phase diagrams ; Powder metallurgy ; Powder metals ; Saturation magnetization ; Scanning electron microscopy ; Sintering ; Thermodynamics ; Titanium carbide ; Tungsten ; Tungsten carbide ; Vacuum furnaces ; Vickers hardness ; Wear resistance ; Cobalt
  8. Source: International Journal of Refractory Metals and Hard Materials ; Volume 30, Issue 1 , January , 2012 , Pages 42-47 ; 02634368 (ISSN)
  9. URL: http://www.sciencedirect.com/science/article/pii/S026343681100117X