Mold Casting Method Research Articles

Hierarchical ultrafine-grained/nanocystalline Al-based bulk alloy with high strength and large plasticity

An in-situ ultrahigh-strength ductile Al-based bulk alloy was produced by copper mold casting method. According to the microstructural investigations, ultrafine-grained/nanocrystalline eutectic colonies with length-scale heterogeneity of lamellar structure have been observed, besides few primary Ag51Y14 phase with a size scale of 1–5 μm. The macroscopic and microscopic structural heterogeneities are able to achieve high strength of up to 1.24 GPa and large compressive plasticity of ∼26%, which is considered to be attributable to the hierarchical network of strengthening intermetallic phases combining with deformable α-Al solid solution suppressing the propagation of microcracks or shear bands.

Radial and longitudinal variations in the Young's modulus of a Zr55Al10Ni5Cu30 bulk metallic glass rod

Abstract Radial and longitudinal variations in the Young's modulus of a Zr55Al10Ni5Cu30 metallic glass cylindrical rod were examined by means of nanoindentation. The metallic glass rod, 2.4 mm in diameter, was prepared using a novel mold-casting method designed to suppress crystallization resulting from the heterogeneous nucleation originating from slag covering a molten alloy. In this study, Young's modulus was measured using a multiple partial unloading technique with a spherical indenter. In general, it is assumed that the cooling rate of a metallic glass rod depends on the radius of its cross section. However, no significant difference was found in the measured Young's modulus.

Magnetocaloric effect in Er-Al-Co bulk metallic glasses

A series of Er-Al-Co bulk metallic glasses (BMGs) have been prepared by the copper mold casting method. The glass forming ability and magnetocaloric effect (MCE) for these alloys have been investigated. The second-order magnetic transition from para-magnetic to ferromagnetic states takes place at about 9 K. These BMGs exhibit excellent MCE because of their large effective magneton number; Er56Al24Co20 BMG has a maximum entropy change and refrigeration capacity of 16.06 J kg−1 K−1 and 546 J kg−1, respectively, under the field of 50 kOe (10 kOe=795.775 kA/m) indicating that these BMGs are potential candidate magnetic materials for hydrogen liquefaction.

Formation and Thermal Stability of Cu-Based Metallic Glasses with High Glass-Forming Ability

Cu-based Cu-Zr-Al metallic glass samples with diameters of more than 10 mm could be produced in a composition range of 45 to 52 (at. pct) Cu, 41 to 47 at. pct Zr, and 6 to 10 at. pct Al by a copper mold casting method. The best glass-forming ability was obtained for the Cu47Zr45Al8 alloy, and the glassy sample with a diameter of 15 mm was fabricated. The minor addition of Ag or Dy can enhance the glass-forming ability of the Cu47Zr45Al8 alloy, which decreases the liquidus temperatures, leading to increase in the reduced glass transition temperature. Fully glassy samples with diameters up to 20 mm were obtained for a (Cu0.47Zr0.45Al0.08)98Dy2 alloy.

Glass-forming ability and corrosion resistance of Zr-based Zr–Ni–Al bulk metallic glasses

Zr–Ni–Al metallic glass samples with diameters above 10mm could be produced in a wide composition range of 54–64at.% Zr, 21–27at.% Ni, and 11–21at.% Al by a copper mold casting method. The best glass-forming ability was obtained for Zr60Ni25Al15 and Zr58Ni27Al15 alloys, and the glassy samples with diameters up to 15mm were fabricated. The Zr60Ni25Al15 bulk metallic glass possesses high compressive yield strength of over 1740MPa with large plastic strain above 3.0%, and the mechanical properties and fracture mode are almost independent of the cast sample size or the position within the rod where the samples have been machined. In addition, the bulk metallic glass shows high corrosion resistance in chloride-ion-containing solutions.

Effects of C Addition on Glass-Forming in FeCPSiBMoMn Bulk Metallic with Good Soft-Magnetic Properties

The effect of C substitution on the glass forming ability (GFA) and soft magnetic properties of Fe-based bulk metallic glasses (BMG) Fe79.4-xCxSi3.5B5.1P8.9Mo3Mn0.1(x = 4.2, 5.2, and 7.0) alloys have been investigated. It is revealed that fully glassy alloy rods with diameters up to 4 mm can be prepared by conventional copper mold casting method even using the low-cost industrial Fe-P master alloy. Properly substituting of Fe by C gives rise to an enhancement of GFA. Moreover, all the samples exhibit good soft magnetic properties with high saturation magnetization up to 1.16 T and low coercivity of 204 A/m.

Simplest Method for Creating Micropatterned Nanostructures on PDMS with UV Light

The fabrication of micropatterned structures on PDMS is a critical step in soft lithography, microfluidics, and many other PDMS-based applications. To substitute traditional mold-casting methods, we develop a simple method to create micropatterned nanostructures on PDMS in one step. After exposing a flat PDMS surface to a UV pen lamp through a photomask (such as a TEM grid), micropatterned nanostructures can be formed readily on the PDMS surface. We also demonstrate that fabricated PDMS can be used for the microcontact printing of protein immunoglobulin (IgG) on solid surfaces. This method is probably the simplest method of creating micropatterned nanostructures on PDMS reported so far because it does not need casting, surface coating, or chemical reagents. Only a UV pen lamp and a photomask are required, and this method can be performed under ambient conditions without vacuum. We expect that this method will greatly benefit researchers who use PDMS regularly in various applications such as soft lithography and microfluidics.

The Effect of Purification on the Glass-Forming Ability of a Pd-Cu-Si Alloy

The copper mold casting method is now commonly used for preparing bulk metallic glasses (BMGs). In the present work, it was found that, by employing the copper mold casting method, Pd77.5Cu6Si16.5 (at. pct) glassy rods with 1-mm diameter could be prepared, while the ϕ2-mm Pd77.5Cu6Si16.5 casting rod possesses some crystalline phases embedded within the glass matrix, confirming that the critical size of the glassy alloy is about 1 mm. By melt purification with fluxing treatment, the critical size of the glassy rod prepared by copper mold casting is increased to 4 mm. Based on thermal property analysis, it was found that melt purification by the fluxing method can greatly enhance the thermal stability and increase the glass forming ability (GFA) of the Pd-Cu-Si alloys. The as-prepared ϕ4-mm Pd-Cu-Si glassy rod exhibits a reduced glass transition temperature (Trg) of 0.599, a supercooled liquid region (ΔT) of 74 K (74 °C), and a γ parameter of 0.419.

Binary Ni-Ta Bulk Metallic Glasses Designed by Using a Cluster-Plus-Glue-Atom Model

With the aid of the atomic-cluster-plus-glue-atom model (ACPGA model) proposed by Dong et al [1] for bulk metallic glasses (BMGs), the formation and characteristic of Ni-Ta binary BMGs were investigated in this work. Binary glass-forming compositions containing 56.3–62.5 at.%-Ni were obtained by a composition formula [M-Ni6Ta6]Ni3based on the ACPGA model. It was found that Ni-Ta BMGs with a diameter of 2 mm was obtained over a composition range of 59 ~ 62 at.%-Ni by copper mold casting method, which are in good agreement with our model prediction. Newly-developed Ni–Ta BMGs are a kind of extreme materials, which exhibit superior thermal stability (Tg= 993K) and a ultrahigh fracture strength of about 3.5 GPa.

Study on continuous casting of bulk metallic glass

Continuous casting method for massive production of steel, aluminum, copper or other crystalline alloy ingot is a very important industrial technology for its low energy consumption and high productivity. In this study, a new continuous casting method was developed for the massive production of bulk metallic glass ingot with centimeter-scale diameter without length limitation. An intermittent withdrawal procedure was practiced for continuous casting of bulk glassy alloy. The new developed continuous casting method can provide a cooling speed as high as that provided by the stationary mold casting method. A Zr-based glassy alloy rod with a diameter of about 10 mm and length of tens of centimeters was prepared by the continuous casting method for the first time.

Tantalum based bulk metallic glasses

Ta-based bulk metallic glasses with high strength (2.7 GPa) and hardness (9.7 GPa), high elastic modulus (170 GPa) and high density (12.98 g/mm 3) were developed. The best glass forming ability so far for a Ta–Ni–Co system reaches a critical diameter of 2 mm by the copper mold casting method. It shows an exceptionally high glass transition temperature of 983 K and a high crystallization temperature up to 1023 K. The unique mechanical and physical properties make them a promising high strength material.

Glass-forming ability and soft magnetic properties of (Co 0.6Fe 0.3Ni 0.1) 67B 22+ xSi 6− xNb 5 bulk glassy alloys

The glass-forming ability (GFA) and soft-magnetic properties of (Co 0.6Fe 0.3Ni 0.1) 67B 22+ x Si 6− x Nb 5 ( x = 0–1.5) bulk glassy alloys was investigated. The DSC curves show that the (Co 0.6Fe 0.3Ni 0.1) 67B 22+ x Si 6− x Nb 5 bulk glassy alloys have a wide supercooled liquid region (Δ T x) of about 60 K, and high reduced glass transition temperature ( T g/ T l) lies in the range from 0.628 to 0.649. By copper mold casting method, the bulk glassy alloys with diameters up to 4.5 mm can be formed. In addition to high GFA, the Co-based bulk glassy alloys also exhibit good soft-magnetic properties, i.e., saturation magnetization of 0.58–0.61 T, low coercive force of 0.83–1.46 A/m, and high permeability of (1.79–2.2) × 10 4 at 1 kHz under a field of 1 A/m. These Co-based bulk glassy alloys are promising for future applications as a new structural and functional material.

J044042 急冷遠心鋳造で作製したトルクセンサ用Fe_Co_V_2磁歪合金の特性([J04404]知的材料・構造システム(4))

For an application of the magnetostrictive alloy to the ring-type torque sensor, it is necessary that the alloy exhibits large magnetostriction, large coercive force and high strength. We previously developed magnetostrictive Fe_<49>Co_<496gt;V_[at%] alloys by copper mold casting method which exhibited good magnetic property and high torque sensitivity (>1.0[G/Nm]), however, their strengths were lower (450[MPa]) than required strength (800[MPa]). The purpose of this study is improvement in strength due to grain refinement by rapid cooling due to applying the rapid-solidification centrifugal casting method. After centrifugal casting, magnetostrictive rings were heat treated to removal of internal stress applied during rapid cooling process. The annealing temperature and time were 650℃, 850℃ for 3 hours to the ring-sample. Result of each measurements, we obtained the centrifugal casted rings which exhibits the values of torque sensitivity, 0.987[G/Nm] and bending strength, 857[MPa].

Ni基バルク金属ガラスの疲労特性

Fatigue test was carried out on Ni-based bulk metallic glass (BMG) for which there is still no reports on fatigue strength. Test alloy rods with a diameter of 2 mm were prepared in Ni60Zr20Nb15Al5 at% systems by copper mold casting method. The tensile strength (σB) was 2.9 GPa. The test specimens were machined to hourglass shape type with a minimum diameter of 0.9 mm. The specimens were tested at a stress ratio of 0.1 and a frequency of 10 Hz. The fatigue limit (σW) and fatigue ratio (σW/σB) in the Ni-based BMG showed high values of 1.68 GPa and 0.58, respectively. The tendency that the σW increased with increasing the σB in BMGs was indicated in the Ni-based BMG. In addition, the fatigue fracture toughness in the Ni-based BMG showed a high value of 14 MPa•m1/2.

Fabrication of bulk metallic glasses at the region of multiple quasi-peritectic reactions

We report that Ca-Cu-Mg bulk metallic glasses (BMGs) can be fabricated at the region of multiple quasi-peritectic reactions by a conventional copper mold casting method, demonstrating that finding a deep eutectic composition is not the sole solution for the fabrication of BMGs. Unusual relationship between the glass transition temperature and the elastic constants of these BMGs were discussed in comparison with other BMGs. These results have implications for exploring new BMGs and understanding the glass formation mechanism.

Synthesis, thermal stability and properties of [(Fe1−xCox)72Mo4B24]94Dy6 bulk metallic glasses

A series of [(Fe1−xCox)72Mo4B24]94Dy6 (x=0.1, 0.2, 0.3, 0.4 and 0.5at.%) bulk metallic glasses (BMGs) in rod geometries with critical diameter up to 3mm were fabricated by copper mold casting method. This alloy system exhibited good thermal stability with high glass transition temperature (Tg) 860K and crystallization temperature (Tx) 945K. The addition of Co was found to be effective in adjusting the alloy composition deeper to eutectic, leading to lower liquidus temperature (Tl). The [(Fe0.8Co0.2)72Mo4B24]94Dy6 alloy showed the largest supercooled liquid region (ΔTx=Tx−Tg=92K), reduced glass transition temperature (Trg=Tg/Tl=0.622) and gamma parameter (γ=Tx/(Tg+Tl)=0.424) among the present system. Maximum compressive fracture strength of 3540MPa and micro-Vickers hardness of 1185kg/mm2 was achieved, resulting from the strong bonding structure among the alloy constituents. The alloy system possessed soft magnetic properties with high saturation magnetization of 56.61–61.78Am2/kg and coercivity in the range of 222–264.2A/m, which might be suitable for application in power electronics devices.

Effect of Pd on microstructures and tensile properties of as-cast Mg–6Al–1Zn alloys

The effects of Pd on the microstructure and mechanical properties of Mg–6Al–1Zn alloys were investigated. Mg–6Al–1Zn–xPd (x = 0–6 wt.%) alloys were prepared using a permanent mould casting method. The microstructure of the as-cast alloys was characterized by the presence of Mg 17Al 12 and Al 4Pd phases. The volume fraction of the Al 4Pd phase was increased by the addition of 1–6 wt.%Pd but the volume fraction of the Mg 17Al 12 phases decreased. At room temperature, the tensile strength increased with increasing Pd addition up to 2 wt.%Pd, and the elongation to fracture decreased with a concomitant increase in the aggregation of the coarse Al 4Pd phase. At 150 °C, the tensile strength increased with the addition of Pd. Therefore, the room and elevated temperature tensile properties of as-cast Mg–6Al–1Zn alloys can be improved by Pd addition.

Effect of Y on microstructure and mechanical properties of duplex Mg–7Li alloys

Mg–7Li– xY ( x = 0–7 wt.%) alloys were prepared by permanent mould casting method, and the microstructure and mechanical properties of the alloys were investigated. The results show that α-Mg and β-Li phases exist in all alloys. The Y-enriched α-Mg phase distributes along the edge of α-Mg phase and in the β matrix of x = 1–7 alloys, and Mg 24Y 5 mainly disperses in the β matrix of x = 3–7 alloys. The strength of the alloy is enhanced by adding Y element, and the elongation is improved with the Y content no more than 3 wt.%. The as-cast Mg–7Li–3Y alloy exhibits an optimum combination of mechanical properties with the ultimate tensile strength, yield strength and elongation of 160 MPa, 144 MPa and 22%, respectively. After solutionized at 400 °C for 3 h with a subsequent aging at 100 °C, Mg–7Li–7Y alloy exhibits high ultimate tensile strength and yield strength, which are improved to 120% and 152% compared with those of the as-cast Mg–7Li alloy, respectively.

Bulk Metallic Glass Formation, Crystallization, and Magnetic Properties of RE&lt;sub&gt;4&lt;/sub&gt;Fe&lt;sub&gt;72&lt;/sub&gt;B&lt;sub&gt;22&lt;/sub&gt;M&lt;sub&gt;2&lt;/sub&gt; Alloys

The RE4Fe72B22M2 (RE=Y, Dy or Nd; M=Nb or Ta) alloys in ribbon and rod forms were prepared by melt spinning and water cooling copper mold casting methods, respectively. Amorphous structure was observed in all ribbon samples, but the results from rod samples indicated that the composition has an important effect on the glass formability. All rod samples with RE=Y or Nd were partly amorphous, while bulk metallic glass (BMG) rod with a diameter of 2 mm was obtained for the Dy4Fe72B22Nb2 alloy. The rare earth and doping elements on the glass formability have been discussed. The effects of post-annealing on the microstructure and magnetic properties of these alloys have been investigated. The results presented here provide a viable method to get fully dense bulk hard magnets.

In situ spherical B2 CuZr phase reinforced ZrCuNiAlNb bulk metallic glass matrix composite

In situ microlevel spherical B2 CuZr phase reinforced Zr49.5Cu36.45Ni4.05Al9Nb1 bulk metallic glass matrix composite was prepared successfully by the copper mold casting method. It was found that mechanical properties of Zr50.5Cu36.45Ni4.05Al9 alloy were improved largely due to the Nb addition. The room-temperature compressive fracture strength and plastic strain for Zr49.5Cu36.45Ni4.05Al9Nb1 rod with a diameter of 5 mm reaches 2037 MPa and 8%, respectively. The improvements are attributed to the precipitation of the spherical B2 CuZr phase distributed uniformly in amorphous matrix, which effectively hampers the propagation of shear bands by deflecting them at the interface and by a multiplication mechanism.