铁中间层钛-钢扩散复合界面组织与性能

利用真空扩散焊方法制备了铁中间层钛-钢扩散焊接头,并采用OM、SEM、EDS、XRD、显微硬度和拉伸试验方法,研究了铁中间层钛-钢扩散复合界面组织和性能。结果表明,在900～1050℃、30 min扩散条件下,Fe、Ti原子在界面处发生了互扩散;钛侧形成βTi+α-βTi+αTi组织,钢侧发生脱碳,铁中间层形成柱状晶组织;拉伸强度随扩散温度升高呈现先增加后减小的趋势,900℃、30 min扩散试样拉伸强度最高,达到260 MPa;拉伸断口具有粗糙断裂区、脆性断裂区及二次断裂区特征,并在断口上检测出TiC、FeTi和Fe2Ti相。

Microstructure and mechanical properties of diffusion bonded joints between titanium and low carbon steel with an iron interlayer

Diffusion bonded joints of titanium/iron interlayer/low carbon steel were prepared by vacuum diffusion welding.Microstructure and properties of the interfaces were examined by means of OM,SEM,EDS,XRD,microhardness and tensile tests.The results show that the interdiffusion of Fe and Ti atoms across the interface results in formation of α-β Ti + α-Ti or β-Ti + α-β Ti + α-Ti microstructure in the side of titanium,and the columnar grains form in iron interlayer and decarburation occurs in steel side,respectively,under the bonding condition of 900 to 1050 ℃ for 30 min.Tensile strength of the joint increases first and then decreases with increase of diffusion temperature and the maximum tensile strength of 260 MPa is achievesd under bonding condition of 900 ℃ for 30 min.The tensile fracture surface shows rough,brittle and second fracture zones and the phases of TiC,FeTi and Fe2Ti are detected on the fracture by XRD.