320 M. F. Amateau, B. Stutzman ,J. C. Conway, halloran mens, designated as DX- 14, was machined into 4 the most aggressive of all cutting configurations test bars 4.76 mm x 6-35 mm x 50-8 mm for The performance of the laminated ceramics was material property characterization. The four test compared to the performance of other typic ound and the edges chamfered te ceramic cutting tools. The testing parameters. 0.762 mm. The corners were finished to 0-0635 the standard tool life tests are given in table 5 mm radius to minimize the stress concentrations The remaining plate was machined into cutting 6. 1 Cutting tests against 718 superalloy tool specimens 12.7 mm x 12 7 mm X 4. 76 mm The density of the DX-14 specimens was mea- Four cutting tool materials were evaluated against sured using Archimedes' principle with water as 718 nickel based superalloy: two grades of TiN the liquid medium. The measured value of 3 88 reinforced Si,N4(SX-5 and RD-3905), one grade g/cc was within 2% of the expected density for of conventional Sic whisker-reinforced alu fully solid material. A four-point bend test with a mina(wG300)and one grade of laminated Sic major span of 31.7 mm, minor span of 15 875 whisker reinforced alumina(DX-14). Four sepa mm,and loading rate of 0.51 in/min was used to rate cutting operations were performed on a 718 measure the modulus of rupture(MOR) of the superalloy billet. The first operation removed DX-14 material. The elastic modulus of this mate- approximately 4 mm of material from a 159 mm rial was measured using a dynamic resonance diameter billet. The second cutting operation technique. The clastic moduli and MOR values removed 2.0 mm of material from the remaining for an average of four tests were 380 GPa and 577 152 mm diameter billet using unused tools of the MPa, respectively same composition as in the first cutting operation The elastic modulus results are within 2% of the The third cutting operation removed 6 mm from rule-of-mixtures(ROM)calculations. The strength the 141 mm diameter billet with a new WG-300 of the DX- 14 laminate is about 8% greater than cutting tool. The last cutting operation removed would be expected for monolithic silicon carbide 2.0 mm from a 133 mm diameter billet using new whisker-reinforced alumina Density measurements SX-5, DX-14 and rD-3905 cutting tools. Flank on the DX-14 material indicate at least 98% of wear in the nose region and in the depth-of-cut theoretical density was obtained during fabrica- region were measured and are referred to as nose tion of this specimen. This indicates that the hot and notch wear, respectively. The average wear pressing parameters are sufficient for complete rates measured after the first cutting operation are densification The agreement between elastic modu- given in Table 6 lus measurements and ROM predictions indicates that good bonding between fiber reinforcement Table 6. Wear rates for cutting tool materials against and matrix was achieved 718 nickel based su Average wear rate for Average wear rate fo 6 WEAR PERFORMANCE TESTS material nose wear(mm/min) notch wear(mm/min) RDC-3905 0.178 0.051 The ceramic tiles were cut into cutting tool specimens sx-5 0.117 0.127 127mm×127mm×476 mm and tested for DX-14 0.053 0127 cutting performance by measuring nose and either WG-300 0.046 0300 notch or flank wear rate versus cutting time. The insert style of the cutting tools used was Greenleaf Corporation Style SNGN-433. The cutting tool specimens were tested against either Inconel 718 superalloy or 4340 steel in lathing operation using 0.75 a negative rake angle configuration. The negative rake angle configuration was chosen because it is 0.50 Table 5. Testing parameters for the standard tool life tests 025 Material Allvac 718 superalloy AlsI 4340 steel Hardness(Rc) 45678 015 213 Depth of cut (mm) 19 Fig. 1. Nose wear of ceramic composite cutting tools against 718 nickel based superalloy.320 AI. F. Amateau, B. Stutzman, J. C. Conway, J. Halloran mens, designated as DX-14, was machined into 4 test bars 4.76 mm X 6.35 mm X 50.8 mm for material property characterization. The four test bars were ground and the edges chamfered to 0.762 mm. The corners were finished to 0.0635 mm radius to minimize the stress concentrations. The remaining plate was machined into cutting tool specimens 12.7 mm X 12.7 mm X 4.76 mm. The density of the DX- 14 specimens was mea￾sured using Archimedes’ principle with water as the liquid medium. The measured value of 3.88 g/cc was within 2% of the expected density for fully solid material. A four-point bend test with a major span of 31.7 mm, minor span of 15.875 mm, and loading rate of 0.51 in/min was used to measure the modulus of rupture (MOR) of the DX-14 material. The elastic modulus of this mate￾rial was measured using a dynamic resonance technique. The elastic moduli and MOR values for an average of four tests were 380 GPa and 577 MPa, respectively. the most aggressive of all cutting configurations. The performance of the laminated ceramics was compared to the performance of other typical ceramic cutting tools. The testing parameters for the standard tool life tests are given in Table 5. 6.1 Cutting tests against 718 superalloy The elastic modulus results are within 2% of the rule-of-mixtures (ROM) calculations. The strength of the DX-14 laminate is about 8% greater than would be expected for monolithic silicon carbide whisker-reinforced alumina. Density measurements on the DX-14 material indicate at least 98% of theoretical density was obtained during fabrica￾tion of this specimen. This indicates that the hot pressing parameters are sufficient for complete densification The agreement between elastic modu￾lus measurements and ROM predictions indicates that good bonding between fiber reinforcement and matrix was achieved. Four cutting tool materials were evaluated against 718 nickel based superalloy: two grades of TiN reinforced S&N, (SX-5 and RD-3905), one grade of conventional SiC whisker-reinforced alu￾mina (WG300) and one grade of laminated Sic whisker reinforced alumina (DX-14). Four sepa￾rate cutting operations were performed on a 718 superalloy billet. The first operation removed approximately 4 mm of material from a 159 mm diameter billet. The second cutting operation removed 2.0 mm of material from the remaining 152 mm diameter billet using unused tools of the same composition as in the first cutting operation. The third cutting operation removed 6 mm from the 141 mm diameter billet with a new WG-300 cutting tool. The last cutting operation removed 2.0 mm from a 133 mm diameter billet using new SX-5, DX-14 and RD-3905 cutting tools. Flank wear in the nose region and in the depth-of-cut region were measured and are referred to as nose and notch wear, respectively. The average wear rates measured after the first cutting operation are given in Table 6. Table 6. Wear rates for cutting tool materials against 718 nickel based superalloy 6 WEAR PERFORMANCE TESTS The ceramic tiles were cut into cutting tool specimens 12.7 mm X 12.7 mm i< 4.76 mm and tested for cutting performance by measuring nose and either notch or flank wear rate versus cutting time. The insert style of the cutting tools used was Greenleaf Corporation Style SNGN-433. The cutting tool specimens were tested against either Inconel 718 superalloy or 4340 steel in lathing operation using a negative rake angle configuration. The negative rake angle configuration was chosen because it is Tool Average wear rate for Average wear rate for material nose wear (mm/min) notch wear (mm/min) RDC-3905 0.178 0.051 sx-5 0.117 0.127 DX-14 0.053 0.127 WG-300 0.046 0.300 1.00 l WG-300 Table 5. Testing parameters for the standard tool life tests Material Allvac 718 superalloy AISI 4340 steel Hardness (Rc) Coolant Feed (mm/rev.) Speed (m/min) Depth of cut (mm) 42 28132 Yes No 0.15 0.25 213 457 I.0 1.9 I 012345678 Cutting Time, min. Fig. 1. Nose wear of ceramic composite cutting tools against 718 nickel based superalloy