[(Fe0.5Co0.5)0.75B0.20Si0.05]96Nb4 Metallic Glasses with Small Cu Additions

Abstract

Recently, (Fe-Co)-B-Si-Nb bulk metallic glasses (BMGs) were produced. Such BMGs exhibit high glass-forming ability (GFA) as well as good mechanical and magnetic properties. These alloys combine the advantages of functional and structural materials. The soft magnetic properties can be enhanced by nanocrystallization. To force the nanocrystallization, small content of Cu was added to the starting composition. In this article, {[(Fe 0.5 Co 0.5 ) 0.75 -Si 0.05 B 0.20 ] 0.96 Nb 0.04 } 100-x Cu x glassy alloys (x = 1, 2, and 3) were chosen for investigation. The GFA and the thermal stability of these alloys were evaluated. The effects of crystallization during heat-treatment processes on the phase evolution and the magnetic properties, including M s , H c , and T c , in these alloys were investigated. The phase analyses were done with the help of the X-ray diffraction patterns recorded in situ by using the synchrotron radiation in transmission configuration.

Viscosity and fragility of the supercooled liquids and melts from the Fe–Co–B–Si–Nb and Fe–Mo–P–C–B–Si glass-forming alloy systems

“…2) of the alloy B, it is clear that T g and T x decrease with addition of 0.5 at.% Cu. This can be easily attributed to the early growth of nano-crystals [25]. The GFA [19] and reduced glass transition temperature T rg ¼ T g /T m, (were T m is usually considered to be the liquidus temperature T L ) are listed in Table 1.…”

“…Moreover, they correlate as well with the maximum achievable geometrical dimensions under which the respective alloys can be cast as fully amorphous samples. 25 Nb 75 (wt.%) prealloy was produced by arc melting pure Fe (99.9 mass%) and pure Nb (99.9 mass%) lumps. The FeNb prealloy, together with Fe and Co lumps (99.9 mass%), crystalline B (99.5 mass%) and crystalline Si (99.99 mass%) were melted together by induction melting under protective Ar atmosphere.…”

Solidification behavior, glass forming ability and thermal characteristics of soft magnetic Fe–Co–B–Si–Nb–Cu bulk amorphous alloys

“…However, coercivity depends on numerous factors such as proportions, compositions and sizes of precipitates, magnetocrystalline anisotropy, magnetostriction, surface roughness, sample shape and sample size. Therefore, assessing the exact mechanism behind H c variations with Cu addition is difficult and it still remains unclear as it was also pointed out in a recent study of Stoica et al [26] for the same alloy system. Nevertheless, further studies are needed to clarify observed dependences of H c variations in this particular alloy.…”

Crystallization Kinetics of Fe76.5−x C6.0Si3.3B5.5P8.7Cu x (x = 0, 0.5, and 1 at. pct) Bulk Amorphous Alloy

“…[34] However, minor additions of Cu may change the crystallization behavior of Fe-based BMG. For example, in (Fe, Co)-B-Si-Nb BMGs with Cu additions, Stoica et al [35,36] reported the formation of a-Fe phase, while in the base alloy typically the complex Fe 23 B 6 phase precipitates upon heating. [35] Ohkubo et al [37] observed special orientation relationship between fcc-Cu and a-Fe primary phase in Fe-Zr-BCu amorphous alloy.…”