摘要
为分析原位合成Cr3C2-NiCr金属陶瓷激光沉积层结合区各组织的生成机制，以质量分数为Ni25％-Cr65％-石墨10％能量色散光谱单元素混合粉为原料原位合成激光沉积层，利用光学显微镜、X射线衍射仪、扫描电子显微镜（X射线能谱仪）等手段研究沉积层结合区显微组织特点，结合激光熔池冶金热力学过程，分析结合区显微组织形成机制。结果表明，Cr3C2-NiCr金属陶瓷层主要由Cr3C2、Cr7C3和Ni基固溶体组成，沉积层与45#钢基体的结合区分为共晶区、枝晶区和平面晶区。根据石墨在Cr-Ni熔池中溶解进程，可以得到结合区碳化物的生长过程，即枝晶前沿生长出Ni＋M33C6共晶，并包围低熔点合金生长出壳状M7C3碳化物，在熔池中生成Cr3C2-NiCr金属陶瓷。
To analyse the growing mechanism of bond zone in cermet Cr3 C2-NiCr coating, which is made through in situ laser deposition, in situ, laser deposit coatings is compounded with Ni25-Cr65-graphite10 （mass fraction： %） powder mixture. The bond zone microstructures coatings are studied by optical microscope, X-ray diffraction and scan electron microscope （energy dispersive X-ray detector）. Following analysis of the laser melt metallurgical thermodynamics, the growing mechanism of the bond zone microstructures is elucidated. The results show that the bond zone of cermet Cr3C2-NiCr coatings constitutes three different zones, eutectic, dendritic and planar. With the study of the process of graphite dissolution in Cr-Ni laser melt, the growth mechanism of carbides in the bonding zone is revealed. Ni＋M23C6 eutectic is formed on the front of the dendrites, the shell-shaped M7C3 grows and surrounds the low melting point alloy, and the cermet Cr3 C2-NiCr is generated in laser melt.
出处
《光学学报》
EI
CAS
CSCD
北大核心
2014年第13期291-296,共6页
Acta Optica Sinica
基金
国家自然科学基金（11204071、51171118）
