Zhou Chen, Jin Ding, Zhang Qiaoxin, Yu Jingui
School of Mechanical and Electronic Engineering, Wuhan University of Technology 122 Luoshi Road Wuhan 430070 P. R. China
RSC Adv. 2019 Mar 29;9(18):10064-10071. doi: 10.1039/c8ra10149c. eCollection 2019 Mar 28.
Interfacial bonding strength is critical to the service life of components in the remanufacturing field. To identify the interfacial mechanical properties, a nickel-based Inconel 625 alloy powder was deposited on the AISI 1045 steel substrate by direct laser deposition. The effects of post-heat treatment on the phase transformation, composition segregation and residual stress releasing near the interface were investigated. A series of microstructural characterizations, such as SEM, FE-SEM, EDS and XRD, were used. By uniaxial tensile experiments, the interfacial bonding strength with/without post-heat treatment were compared, we found that the interfacial bonding strength of original specimen (556.8 MPa) was stronger than that of post-heat treatment (452.3 MPa). This was attributed to the fact that the thermal expansion coefficient of Inconel 625 powder ( = 14.7) was less than that of the AISI 1045 substrate ( = 15.6), resulting in the compressive residual stress at the edge of interface. After post-heat treatment, the release of beneficial compressive residual stress and the change of phase composition near the interface were the reasons for the decrease of interfacial bonding strength. These results indicated that post-heat treatment is not suitable for all heterogeneous bonding materials. This kind of material matching ( < ) is more advantageous to remanufacturing field.
界面结合强度对再制造领域中零部件的使用寿命至关重要。为了确定界面力学性能，通过直接激光沉积将镍基Inconel 625合金粉末沉积在AISI 1045钢基体上。研究了后热处理对界面附近相变、成分偏析和残余应力释放的影响。使用了一系列微观结构表征方法，如扫描电子显微镜（SEM）、场发射扫描电子显微镜（FE-SEM）、能谱仪（EDS）和X射线衍射仪（XRD）。通过单轴拉伸试验，比较了经过和未经过后热处理的界面结合强度，发现原始试样的界面结合强度（556.8 MPa）高于后热处理后的界面结合强度（452.3 MPa）。这是由于Inconel 625粉末的热膨胀系数（α = 14.7）小于AISI 1045基体的热膨胀系数（α = 15.6），导致界面边缘产生压缩残余应力。后热处理后，有益压缩残余应力的释放以及界面附近相组成的变化是界面结合强度降低的原因。这些结果表明，后热处理并不适用于所有异种结合材料。这种材料匹配（α < α）对再制造领域更为有利。
