| Because of the structure characteristics of long-range disorder and short-range order, amorphous alloys that are also called metallic glasses exhibit excellent physical and chemical properties.Among these systems, Fe-base amorphous alloys have been widely used in the field of production and manufacturing of electronic components and power equipment transformers for its outstanding electromagnetic characteristics. Fe-based amorphous alloys are capable to be a new type of energy-saving and environmentally-friendly materials with its own advantages on low energy consumption and low cost in application process.However, by decades of scientific researches and explorations, Glass forming ability of Fe-based amorphous alloys are still lower than other systems, and can only get the samples with maximum size only a few millimeters. At the same time, almost all Fe-based amorphous alloys that have been widely applied as commercial products with excellent performances are manufacture into ribbons and the thickness of obtained products are limited in several micrometers. Therefore, by exploring and developing new Fe-based amorphous alloys with low cost, high glass forming ability and excellent performance to break the bottleneck in low glass forming ability and monosized product morphology, is significant for us to understand the formation mechanism of amorphous alloy, accelerate the commercialization of the Fe-base amorphous alloys products and broaden its application field.In this paper, we developed quinary Fe-B-Y-Nb-Ti BMGs by using high-purity elements and low-purity industrial raw materials, including a Fe-B alloy and sponge titanium. By using cheap titanium sponge replaced the original precious metal element Nb in the alloy, we have successfully developed a new type Fe-based bulk metallic glasses with nominal compositions of (Fe71.2B24Y4.8)96Nb4-xTix (x=0,1,2,3,4), that not only reduce the cost of initial alloys but also improve the glass forming ability of alloys obviously. By analyzing the experimental data we get the following conclusions:The STA thermal scans of as-cast (Fe71.2B24Y4.8)96Nb4-xTix (x=0,1,2,3,4) amorphous samples showed that addition of Ti element can obviously improve the glass forming ability of alloys. when the content of Ti element increases from 0 at.% to 4 at.%, the glass transition temperature (Tg) and the onset temperature of the crystallization peaks (Tx) of the samples with completely amorphous structure monotonically increased first and then gradually decreased. When the content of Ti element x=2 at.%, the nominal composition of (Fe71.2B24Y4.8)96Nb2Ti2 alloy exhibited the best glass forming ability (Dmax=6 mm), which showed the largest supercooled liquid regions Δ Tx=103 K, the biggest reduced glass transition temperature Trg=0.608 and parameters y=0.423.The saturation magnetization (Ms) of samples decreases gradually with Ti substitution increasing, and coercivity (Hc) fluctuated seriously caused by the influence of various external factors. The results showed that there is no direct relation between glass forming ability and saturation magnetization or coercivity..In addition, compared with its rod shape glassy state (low cooling rate), the (Fe71.2B24Y4.8)96Nb2Ti2 ribbon samples (high cooling rate) presented more excellent soft magnetic properties with higher saturation magnetization and lower coercivity, which is expected from the resulted different magnetic domain structures in the ribbon and bulk samples caused by different fabrication processes that corresponding differing cooling rates. Finally, We also investigated the mechanical properties of the new quinary Fe-B-Y-Nb-Ti BMGs system, which exhibits high compressive fracture strength σf≥ 3000MPa, and further measure of compressive fracture strength of (Fe71.2B24Y4.8)96Nb2Ti2 BMGs even reached up to 3400 MPa with Vickers microhardness Hv0.1=1208. These results demonstrate that the present Fe-based bulk metallic glasses might be a potential candidate for commercial applications with low cost and good performance. |
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