等轴晶
材料科学
奥氏体
微观结构
铁氧体(磁铁)
冶金
合金
针状铁素体
复式(建筑)
β铁氧体
针状的
复合材料
融合
激光器
光学
贝氏体
DNA
语言学
哲学
生物
遗传学
物理
作者
X.C. Li,Fei Shen,Wen Xiang Du,Lijun Cao,L. Pan,Tiejun Ma,Xiaoying Fang
标识
DOI:10.1016/j.msea.2023.145908
摘要
Distinctive microstructures and distributions of novel duplex (ferrite δ + austenite γ) stainless steel can be fabricated using in-situ alloying of Fe–Cr–Mn alloy and pure Ni powders by tuning laser energy density in powder bed fusion. At low-level energy density (∼60 J/mm3), ferrite solidification dominates and results in bimodal ferrite of columnar and equiaxed grains. At medium energy density (∼100 J/mm3), fine acicular Widmanstätten austenite satisfying the Nishiyama-Wassermann orientation relationship was produced within the coarse grains of δ, which is the predominant phase although ferrite and austenite solidification occur. At high-level energy density (∼194 J/mm3), ferrite and austenite solidification occur and the resultant microstructure consists of nearly equivalent fine equiaxed-grained δ and γ. The key difference in the microstructure was attributed to the different melt pool overlapping and types, which can be characterized by the size and local ratio of Cr equivalent (Creq) and Ni equivalent (Nieq) values (Creq/Nieq). The melt pool characteristics fundamentally determine the local solidification and transformation mode at different energy densities. The testing results have shown that the novel duplex stainless steel possesses excellent mechanical properties compared to conventionally-manufactured counterparts.
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