摘要
激光增材制造技术作为新型逐层熔合制造工艺可以根据要求制备元素成分梯度变化的金属材料。试验设计了一种由两种不锈钢粉末按均匀配比变化而成的梯度成分样品,首先利用热力学计算软件预测了材料的相组织成分占比、力学性能变化;然后采用多路送粉激光熔覆工艺进行样品制备;进而利用微区X射线荧光光谱仪、金相显微镜和显微维氏硬度计结合流体微探应变技术对该梯度材料进行了微观区域的精细成分、显微组织和硬度的统计分布表征研究。表征结果中该梯度成分样品不同区域元素含量、金相组织、硬度力学性能的差异变化规律同热力学软件计算的结果基本符合。通过研究成分梯度变化区域元素成分对区域的组织状态和材料力学性能的影响,结果表明样品表面硬度分布拐点和陡降区与Ni元素的变化和板条状马氏体的出现密切相关,同时316L奥氏体组织呈不连续骨架分布,而JY-Fe45A区域显示存在大量板条状马氏体,且晶粒组织粗大。最后利用基于等静压的流体微探应变无损检测方法与显微维氏硬度计相结合分析了样品中力学性能异常区域的原因,并发现了现有打印制造工艺的不足。
As a new layer-by-layer fusion manufacturing process,the laser-enhanced additive manufacturing technology can be used to prepare metal materials with gradient variation of elemental composition according to the requirements.A gradient composition sample composed of two stainless steel powders with uniform ratios was designed.Firstly,the phase composition and mechanical properties of the material were predicted using thermodynamic calculation software.Then,the sample was prepared by multi-channel powder feeding laser cladding process.Finally,the statistical distribution of fine composition,microstructure and hardness of the gradient material in micro-regions were characterized using micro-zone X-ray fluorescence spectrometer,metallurgical microscope and micro Vickers combined with fluid microprobe strain technology.The results showed that variations of element content,metallographic structure,hardness and mechanical properties in different regions of the gradient component sample were basically consistent with those calculated by thermodynamic software.The influence of elemental composition in component gradient changing regions on the structural state of region and mechanical properties of material was studied.It indicated that the inflection point and steep drop zone of hardness distribution were closely related to the changes of Ni element and the appearance of lath martensite.Meanwhile,the 316L austenite structure showed discontinuous skeleton distribution,while the JY-Fe45A region contained much lath martensite with coarse grain structure.At last,the reason of abnormal mechanical properties in samples was analyzed by combining isostatic pressure-based fluid microprobe strain non-destructive testing method with micro-Vickers.The shortcomings of existing printing process were found.
作者
冯光
李冬玲
刘宗鑫
沈学静
王海舟
贾云海
FENG Guang;LI Dong-ling;LIU Zong-xin;SHEN Xue-jing;WANG Hai-zhou;JIA Yun-hai(Testing Institute,Central Iron and Steel Research Institute,Beijing 100081,China;Beijing Key Laboratory of Metal Material Characterization,Beijing 100081,China;NCS Testing Technology Co.,Ltd.,Beijing 100081,China)
出处
《冶金分析》
CAS
北大核心
2019年第11期1-8,共8页
Metallurgical Analysis
基金
国家重点研发计划材料基因工程关键技术与支撑平台（2016YFB0700203)
关键词
微区X射线荧光光谱法
激光打印增材制造
成分分布
显微组织
硬度分布
micro-zone X-ray fluorescence spectrometry
laser printing additive manufacturing
composition distribution
microstructure
hardness distribution
