Research Of PDC For Cutting Tool

A general introduction on research and development(R&D) of polycrystalline diamond compacts(PDC) is given in this thesis.R&D for PDC materials applied for cutting tools needs to be further enhanced in our county.In this work,the PDC sintering processes is optimized using orthogonal experiments.Meanwhile the sintered PDC samples are studied by various methods such as SEM,EDS,XRD,Raman,etc.With the optimized experimental conditions,we have prepared the high quality PDC materials for cutting tools.The major work in this thesis includes the following parts:(1) The pressure and temperature of sintering cell are confirmed.The temperature distributing in the cell is simulated by ANSYS soft.The change rule of pyrophyllite weight loss,compression strength and tensile strength are investigatedat different temperatures,and pyrophyllite heat treatment process is also studied.The high-pressure and high- temperature sintering processes for PDC materials are optimized using orthogonal experiments. (2) The PDC materials for cutting tools are sintered in our work by way of mixing and infiltration sintering technique.The character of sintering thermodynamics & dynamics are analyzed.It concludes that some metal powder mixed with diamond grits,which can be melted under the sintering temperature,is helpful for wetting diamond powder with binders.So that the sintering time can be shorten and its microstructure will be more uniform.(3) The wear resistance,micro-hardness and compression strength of PDC sintered under different condition are investigated.Moreover the rule of wear ratio along PDC radial is also investigated.The control and adjustment principles of sintering process are summarized.(4) The PDC resistant-heat is studied by choosing different materials and according to united strength between polycrystalline diamond and tungsten carbide.Then a process method is made that improve its resistant-heat and eligibility ratio.(5) Some inserts are made for cutting Al-alloy with our PDC.Through the cutting experiments with different parameters,influence rule and quality variety characters are studied.The abrasion character are investigated while cutting high-silicon Al-alloy.So abrasion mechanism are analyzed and discussed.Meanwhile cutting bits character and cutting mechanism while cutting materials are also researched.Finally cutting experiment is carried out with our PDC,and compared with Korea PDC.Some innovations are made in this thesis:(1) The assembly cell is optimized by ANSYS.According to this result temperature distribution control is taken in the cell in order to decrease temperature grads owing to the enlarged cell.So the PDC temperature difference is decreased between edge and center.Therefore it will increase PDC sintering uniformity.(2) A method of mixed and infiltration sintering technique are used for PDC synthesis.It is found that the sintering time can be shorten and a even microstructure can be obtained.(3) A mixture of CBN-Al-Co is considered as a transition layer of PDC.It can improve resistant-heat and eligibility ratio of PDC.Simultaneity it can restrain delamination and chip of PDC.The resistant-temperatuare of PDC can be improved about 200℃when it is sintered with titanium coated diamond.(4) A result is made about corresponding connection of temperature and heating current in the cell by regress analysis,Y=1.1553X1.799.It is found that quanity of heat in the cell is produced by joule effect.(5) Abrasion character and rule are found quickly by cutting superhigh-Si Al-alloy.(6) PDC is researched under industry condition.And research production is applied into industrialization without examination phase.The cutting life of our sintered PDC is alike with Korea PDC,so the quality of our PDC is the same with Corea's.