Copper Mold Injection Casting Research Articles

Structural and magnetic properties of Fe76P5(Si0.3B0.5C0.2)19 amorphous alloy

Recently, bulk amorphous alloys were produced in the Fe–B–Si–P–C system with high glass forming ability, excellent magnetic properties and the advantage of containing no expensive glass-forming elements, such as Ga, Y, Cr or Nb, having, therefore, a good perspective of commercial applications. In the present work, the Fe76P5(Si0.3B0.5C0.2)19 amorphous alloy prepared by two quenching techniques has been studied. Amorphous ribbons of about 40μm thick were obtained by planar-flow casting together with cylinders having 1 and 2mm diameter produced by copper mold injection casting. All the samples appear fully amorphous after X-ray diffraction analysis. A comprehensive set of thermal data (glass, crystallization, melting and liquidus temperatures) were obtained as well as a description of the melting and solidification processes. Mechanical microhardness tests showed that the samples have a hardness of 9.7±0.3GPa. Good soft-magnetic properties were obtained, including a high magnetization of 1.44T and a low coercivity (4.5A/m for ribbons and 7.5A/m in the case of 1mm rod samples, both in as-cast state). Thermomagnetic studies showed a Curie temperature around 665K and the precipitation of new magnetic phases upon temperatures of 1000K. Furthermore, the frequency dependence of magnetic losses at a fixed peak induction was studied. The results suggest the occurrence of a fine magnetic domain structure in bulk samples. The good soft magnetic properties of the bulk metallic glass obtained by copper mold casting for this particular Fe-based composition suggests possible applications in transformer cores, inductive sensors and other devices.

Formation and thermal stability of new Zr–Cu-based bulk glassy alloys with unusual glass-forming ability

The simultaneous addition of Al and Ag to Zr–Cu binary alloys increased in the stabilization of supercooled liquid, the reduced glass transition temperature and γ value, leading to greatly enhance the glass-forming ability (GFA). The Zr–Cu–Ag–Al glassy alloy samples with diameters above 15 mm were obtained in the wide composition range of 42–50 at% Zr, 32–42 at% Cu, 5–10 at% Ag, and 5–12 at% Al. The best GFA was obtained for Zr 48Cu 36Ag 8Al 8 alloy, and the glassy samples with diameters up to 25 mm were fabricated by an injection copper mold casting. The Zr 48Cu 36Ag 8Al 8 glassy alloy exhibited high tensile and compressive fracture strength of over 1800 MPa.

Fabrication of Cu–Zr–Ag–Al glassy alloy samples with a diameter of 20 mm by water quenching

The melting behavior, thermal stability, and glass-forming ability (GFA) of Cu84−xZrxAg8Al8 (x = 42 to 50) glassy alloys were investigated. The alloy with x = 46 exhibits the highest reduced glass transition temperature (Trg). However, the best GFA was obtained for alloy with x = 48 corresponding to the largest supercooled liquid region (ΔTx) and a deep eutectic composition. At the best GFA composition, full glassy samples with diameters of over 20 mm could be fabricated by injection copper mold casting and water quenching without flux. The underlying mechanism of the unusual GFA of the alloy is discussed.

Preparation of Cu<SUB>36</SUB>Zr<SUB>48</SUB>Ag<SUB>8</SUB>Al<SUB>8</SUB> Bulk Metallic Glass with a Diameter of 25 mm by Copper Mold Casting

The Cu 36 Zr 48 Ag 8 Al 8 alloy exhibits very high glass-forming ability. We have succeeded in synthesizing a Cu 36 Zr 48 Ag 8 Al 8 bulk glassy alloy with a diameter of 25 mm using the conventional copper mold injection casting. The absence of a crystalline phase was confirmed by X-ray diffraction and differential scanning calorimetry examinations. The critical cooling rate for formation of a glassy phase for the Cu 36 Zr 4 Ag 8 Al 8 alloy was estimated to be less than 6.4 K/s. High glass-forming ability and high strength might contribute to its commercial application for the Cu 36 Zr 48 Ag 8 Al 8 bulk metallic glass.

Bulk metallic glass formation in Ni–Zr–Nb–Al alloy systems

Ni-based metallic glasses containing no metalloids are developed in Ni–Zr–Nb–Al alloy system. A partial replacement of Zr with Nb in Ni–Zr–Al alloys significantly enhances the glass-forming ability (GFA) and enlarges the undercooled liquid region during continuous heating of glassy ribbons. A quaternary Ni–Zr–Nb–Al metallic glasses exhibit large undercooled liquid region (>50 K), indicating high glass-forming ability of the alloy. The glass transition and crystallization temperatures of a quaternary Ni 61Zr 28Nb 7Al 4 alloy are 848 and 898 K, respectively, exhibiting a wide undercooled liquid region of 50 K. A complete Ni 61Zr 28Nb 7Al 4 glassy rod (φ1 mm) can be prepared by copper mold injection casting.

High-strength Cu–Ti-rich bulk metallic glasses and nano-composites

Abstract Cu47Ti34Zr11Ni8, Cu47Ti33Zr11Ni8Fe1 and Cu47Ti33Zr11Ni8Si1 bulk glassy alloys were prepared by injection copper mold casting. Mechanical properties, glass-forming ability, thermal stability and microstructural characteristics of as-cast rods were investigated. Calorimetric studies indicate a beneficial role of small Si or Fe addition on the thermal stability of Cu–Ti–Zr–Ni bulk glassy alloys. Compression tests reveal fracture strengths of 2040 to 2190 MPa, Young's moduli of 100 to 109 GPa and elastic strains up to 2.4%. The Si-containing glassy alloy exhibits a plastic elongation of 2.2%. The significant increase in plasticity observed for the Si-containing alloy is due to a special bimodal composite structure consisting of nano-scaled Cu crystals homogeneously dispersed in the bulk metallic glass matrix. The increase of the global plasticity can be explained by the formation of multiple shear bands that make the glassy alloy resistant to crack propagation.

Ni-based amorphous alloys in the Ni–Zr–Al–Y system that have high glass forming ability and large undercooled liquid regions

Ni-based amorphous alloys containing no metalloids are developed in the alloy system Ni–Zr–Al–Y. A partial replacement of Zr by Y significantly enhances the glass-forming ability and enlarges the undercooled liquid region during continuous heating of amorphous ribbons. A quaternary alloy Ni 55Zr 17Al 11Y 17 exhibits large undercooled liquid region (54 K) implying high glass-forming ability of the alloy. The glass transition and crystallization temperatures of the quaternary alloy obtained in a differential scanning calorimetry are 717 and 771 K, respectively. A fully amorphous rod (Φ1 mm) and a rod (Φ2 mm) having a high volume fraction (∼80%) of the amorphous phase can be prepared by copper mold injection casting.