Tham khảo tài liệu 'modern tribology handbook 2010 part 10', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | FIGURE Nanoindentation curves for three different PVD coatings TiB2 TiN and CrN. The obtained hardness values and Young s moduli GPa were 53 566 TiB2 30 450 TiN and 25 330 CrN respectively. FIGURE a Photograph of a four-point beam-bending device suitable for operation in an SEM. A indicates the coated test specimen B the load cell and C the acoustic detector. b A representative plot of crack density o and acoustic emission line vs. coating and composite strain respectively for a 4- tm PVD TiN-coating on ASP2030 HSS. The insert shows a top view of a coating stressed beyond the fracture limit. c Critical strains of multilayered TiN TaN coatings compared with those of the single TiN and TaN layers. The light bars represent the composite strain while the dark bars represent the coating strain for which the residual stress has been subtracted. From Wiklund U. Hedenqvist P. and Hogmark S. 1997 Multilayer cracking resistance in bending Surf. Coat. Technol. 97 773-778. With permission. Several investigators have used beam bending to assess the deformability of coatings and to obtain numerical estimates of their fracture resistance and toughness Ramsey et al. 1991 Oettel and Wiede- mann 1995 Wiklund et al. 1997 . In the device of Figure a the bending load is continuously 2001 by CRC Press LLC FIGURE Nanoindentation curves for three different PVD coatings TiB2 TiN and CrN. The obtained hardness values and Young s moduli GPa were 53 566 TiB2 30 450 TiN and 25 330 CrN respectively. FIGURE a Photograph of a four-point beam-bending device suitable for operation in an SEM. A indicates the coated test specimen B the load cell and C the acoustic detector. b A representative plot of crack density o and acoustic emission line vs. coating and composite strain respectively for a 4- tm PVD TiN-coating on ASP2030 HSS. The insert shows a top view of a coating stressed beyond the fracture limit. c Critical strains of multilayered TiN TaN coatings compared with
