The Study And Design Of High Pressure WC Anvil

We have developed a modeling of effective design of WC anvil by finite element method(FEM).The criterion for crack of WC anvil used in cubic high pressure apparatus(CHPA)has been founded successfully.According to the von Mises criterion,some new type WC anvil have been developed,for example,double-beveled anvil,hybrid-anvil,double-beveled hybrid-anvil,radius anvil,6-2 type WC anvil and rectangular WC anvil.The criterion for crack of WC anvil used in CHPA has been founded successfully.The simulation results indicated that the criterion for crack of WC anvil should make the reference point at the end of bevel edge and the optimum value of the angle and length of the bevel edge should be 13 mm and 41.5 degree.Further more,we performed finite element simulations of high pressure experiment in CHPA to determine the temperature and the stress in WC anvil.A new double-beveled anvil for the synthesis of high-quality diamonds has been described.Our results indicate that the pressure generation of a double-beveled anvil is more efficient than that of a single-beveled anvil.Furthermore,double-beveled anvil can maintain the pressurized seal stability of the sample chamber,which is often sacrificed with improve the pressure of sample cell.A hybrid-anvil and double-beveled hybrid-anvil used in CHPA are developed,which can save weight compared to the traditional anvil.The ultimate attainable cell pressure of a double-beveled hybrid-anvil is about 7.0 GPa,which is more efficient than that of a single-beveled anvil.We note from high pressure experiments that the rate of failure crack decreases and the cost of anvil save after the modification of the anvil.We have developed and analyzed some new functional WC anvil.Our results indicate that the stress concentration of radius anvil can be decreased sharply compared to the traditional anvil.In order to increase the ultimate attainable cell pressure,a 6-2 type WC anvil has been developed.Our results indicate that the ultimate attainable cell pressure of 6-2 type WC anvil is about 9.56 GPa.A new type rectangular WC anvil have been developed too,whose aim is to use for increase the volume of high-pressure cell and synthetic higher quality diamond than traditional anvil.The rectangular WC anvil can increase the volume of cell about 18.9 %compared to the traditional anvil.