Based on ANSYS FEM software, the distribution of residual stress in the diffusion bonding joints between Ti（ C,N） metallic ceramic/interlayer/4OCr steel was calculated and experimentally ver^ed. The results showed t...Based on ANSYS FEM software, the distribution of residual stress in the diffusion bonding joints between Ti（ C,N） metallic ceramic/interlayer/4OCr steel was calculated and experimentally ver^ed. The results showed that the trend on the distribution of residual stress field in the joints was not changed with the use of interlayer. The maximum residual stress was always located in metallic ceramic with area ranging from 1 mm to 4 mm to the interlayer. The maximum residual stress in the joints was also affected by diffusion temperature. The satellite pulse current during the initial stage on diffusion bonding can promote the formation of liquid film at the interface, by which diffusion temperature and loading pressure can be greatly decreased. The crack initiation was easily produced at the corner of Ti （ C, N） metallic ceramic close to the interlayer. If a higher residual stress produced in the joints, the crack was propagated into the whole ceramic.展开更多
Ti(C,N)-TiB2 cermets were fabricated from Ti(C,N), TiB2, Co and WC powder mixtures via a vacuum hot pressing process. The influence of TiB2 content on their microstructures and mechanical properties was investigated. ...Ti(C,N)-TiB2 cermets were fabricated from Ti(C,N), TiB2, Co and WC powder mixtures via a vacuum hot pressing process. The influence of TiB2 content on their microstructures and mechanical properties was investigated. As a result of the elevated TiB2 contents, two types of corerim microstructures were present in the Ti(C,N)-TiB2 cermets, and remarkably improved mechanical properties were achieved. With the increase of TiB2 content, the flexural strength, fracture toughness and hardness of the Ti(C,N)-TiB2 cermets first increased, and then decreased, while their relative density consistently decreased. Attributed to an integration of the intergranular and intrangranular fracture behaviors, the Ti(C,N)-TiB2 cermets with 20 wt% TiB2 content exhibited the best overall properties with the relative density, hardness, fracture toughness and flexural strength at 99.3%, 1 995 HV, 7.92 MPa·m1/2 and 1 114 MPa, respectively. The underlying mechanism for their enhanced properties was studied in detail.展开更多
基金The authors are grateful to the financial support for this research from National Natural Science Foundation of China （Grant No. 51175259） , Jiangsu Science and Technology Planning Project （No. BK2011494） and University Science Research Project of Jiangsu Province （ 11KJAd30005 ）.
文摘Based on ANSYS FEM software, the distribution of residual stress in the diffusion bonding joints between Ti（ C,N） metallic ceramic/interlayer/4OCr steel was calculated and experimentally ver^ed. The results showed that the trend on the distribution of residual stress field in the joints was not changed with the use of interlayer. The maximum residual stress was always located in metallic ceramic with area ranging from 1 mm to 4 mm to the interlayer. The maximum residual stress in the joints was also affected by diffusion temperature. The satellite pulse current during the initial stage on diffusion bonding can promote the formation of liquid film at the interface, by which diffusion temperature and loading pressure can be greatly decreased. The crack initiation was easily produced at the corner of Ti （ C, N） metallic ceramic close to the interlayer. If a higher residual stress produced in the joints, the crack was propagated into the whole ceramic.
基金Funded by the National Natural Science Foundation of China(Nos.21571095,51404157)the Zhejiang Provincial Natural Science Foundation of China(No.LY17E050003)+2 种基金the Taizhou Science and Technology Project(No.15gy54)the Open Research Program of Zhejiang Provincial Key Laboratory for Cutting Tools(No.ZD201501)the Open Foundation of Jiangsu Key Laboratory of Precision and Micro-Manufacturing Technology and the Public Projects of Zhejiang Province(Nos.2017C31118,2016C31049)
文摘Ti(C,N)-TiB2 cermets were fabricated from Ti(C,N), TiB2, Co and WC powder mixtures via a vacuum hot pressing process. The influence of TiB2 content on their microstructures and mechanical properties was investigated. As a result of the elevated TiB2 contents, two types of corerim microstructures were present in the Ti(C,N)-TiB2 cermets, and remarkably improved mechanical properties were achieved. With the increase of TiB2 content, the flexural strength, fracture toughness and hardness of the Ti(C,N)-TiB2 cermets first increased, and then decreased, while their relative density consistently decreased. Attributed to an integration of the intergranular and intrangranular fracture behaviors, the Ti(C,N)-TiB2 cermets with 20 wt% TiB2 content exhibited the best overall properties with the relative density, hardness, fracture toughness and flexural strength at 99.3%, 1 995 HV, 7.92 MPa·m1/2 and 1 114 MPa, respectively. The underlying mechanism for their enhanced properties was studied in detail.
