316L分层实体扩散焊接头微观组织与力学性能分析

Analysis of microstructure and mechanical properties of 316L layered solid diffusion bonded joint

对316L薄板材及316L分层实体扩散焊接头,开展-196,20,600℃力学性能试验及微观组织分析。结果表明,扩散焊界面微观金相组织与母材相同。同一试验温度下,垂直于扩散界面方向抗拉强度均小于平行于扩散焊界面方向抗拉强度;3种试验温度下,扩散焊接头抗拉强度均高于0.9倍的母材抗拉强度;随着温度升高,扩散焊接头抗拉强度逐渐下降,其中在-196℃试验条件下的扩散焊接头强度远高于20℃和600℃试验条件下的强度试验数据。对拉伸试样进行SEM断口分析,均以韧性断裂为主,随着温度升高,纤维区比例变高,韧窝的尺寸与深度变大,韧性提高;-196℃与20℃的断口形貌以正拉应力的等轴韧窝为主,600℃为指形抛物线韧窝形貌。

For the 316L thin plate and 316L layered solid diffusion bonded joint,the mechanical performance test and microstructure analysis were carried out at-196,20,600℃,respectively.The results show that the microstructure of diffusion bonding interface is the same as that of the base metal.The tensile strength in the direction perpendicular to the diffusion bonding interface is less than that in the direction parallel to the diffusion bonding interface;The tensile strength of the diffusion bonded joint at 3 test temperatures is higher than 0.9 times of the tensile strength of the base metal;With the increase of temperature,the tensile strength of diffusion bonded joints gradually decreases;Among them,the strength of the diffusion bonded joints under the test conditions of-196℃is much higher than the strength test data under the test conditions of 20℃and 600℃.SEM fracture analysis of tensile specimen mainly focuses on ductile fracture,with the increase of temperature,the proportion of fiber area becomes higher,and the size and depth of dimples become larger,and toughness is improved;The fracture morphology at-196℃and 20℃is based on the normal tensile stress of equiaxed dimples.The morphology at 600℃is the morphology of finger-shaped parabolic dimples.