Many alloys produced by Laser Powder Bed Fusion (LPBF) suffer from coarse grains and anisotropic mechanical properties. Here, we investigate how the addition of Ti can cause significant strengthening via grain refinement in a model ferritic stainless steel. We perform LPBF experiments using elemental Fe, Cr, and Ti powders (with significant O impurity in the Fe powder) and perform microstructural analysis by SEM, EDS and EBSD as well as tensile tests on the alloys Fe-19at.%Cr and Fe-19at.%Cr-5at.%Ti. The Fe-Cr alloy displays very large grains after LPBF and a strong cube texture, rendering its mechanical properties similar to a single crystal. In the Fe-Cr-Ti alloy, TiO particle formation in the melt causes strong grain refinement, leading to a texture-free microstructure consisting of equiaxed grains ~1.6 μm in diameter. The 0.2% proof strength of the ternary alloy is more than double that of the binary alloy (281 MPa → 591 MPa), and the work hardening rate is also increased. While the elongation at fracture is reduced for the Fe-Cr-Ti alloy, at ~15 %, it remains sufficient, and samples show ductile fracture surfaces. We estimate that the grain refinement accounts for the majority of the strengthening, however, solid solution strengthening and the effect of the texture are also significant.

激光粉末床熔合（LPBF）生产的许多合金都具有粗大晶粒和各向异性的机械性能。在这里，我们研究了添加钛如何通过模型铁素体不锈钢中的晶粒细化而引起显着的强化。我们使用元素Fe，Cr和Ti粉末（Fe粉末中含有大量O杂质）进行LPBF实验，并通过SEM，EDS和EBSD进行显微组织分析，并对Fe-19at。％Cr和Fe- 19at。％Cr-5at。％Ti。Fe-Cr合金在LPBF之后显示出非常大的晶粒，并具有很强的立方织构，使其机械性能类似于单晶。在Fe-Cr-Ti合金中，熔体中形成的TiO颗粒会导致晶粒细化，从而导致无纹理的微观结构，该组织由直径约1.6μm的等轴晶粒组成。0。三元合金的2％屈服强度是二元合金（281 MPa→591 MPa）的两倍以上，并且加工硬化率也得到提高。尽管Fe-Cr-Ti合金的断裂伸长率降低了约15％，但仍足够，并且样品显示出韧性的断裂表面。我们估计晶粒细化是强化的主要部分，但是固溶强化和织构效果也很重要。