Tensile and Hardness Properties of Cast 6063 Aluminium Rods produced from Sand and Squeeze Casting Moulds

This work presents experimental analysis to determine the effect of sand and squeeze casting methods on the Tensile and Hardness properties of AA6063 Aluminium. Sand and squeeze cast moulds were fabricated and used to produce Aluminium rods. The test samples from cast rods were subjected to Tensile and Hardness tests. The results obtained showed better Tensile and Hardness properties, in the squeeze cast samples that were produced under varied pressure. The hardness of squeeze casting varied from 72.9 to 82.3Hv, while that of sand casting had 70.0Hv. Also, Ultimate Tensile Strength increased with increased pressure in squeeze castings from 178.01 to 194.04MPa and 161.97 in sand castings. Conversely, the mechanical properties of the cast products improved from those of sand casting to squeeze casting. Therefore, squeeze cast products could be used in as-cast condition in engineering applications requiring high quality parts while sand casting may be used in as-cast condition for non- engineering applications or engineering applications requiring less quality parts

Quantitative Characterization of a Belt-cast High-Manganese Steel Microstructure

The description of the solidification process in casting processes with varying product thickness is characterized based on solidification structures, segregations as well as the primary and secondary microstructure. In near-net-shape casting processes, it is particularly challenging to achieve microstructure homogeneity in the as-cast condition, since the degree of forming in production processes up to hot or cold strip is lower than in the production of slabs or thin slabs. The density of shrinkage porosity in belt-cast high-manganese steel (HMnS) will be determined quantitatively using polished microsections. Following the visualization of the primary cast structure, light microscopic images will be obtained using different tint etches. For the evaluation of secondary dendrite arm spacing (SDAS), internally developed software based on ImageJ and Matlab will be used.

Strain-hardening properties of the high-entropy alloy MoNbTaTiVZr processed by high-pressure torsion

An equiatomic MoNbTaTiVZr refractory high-entropy alloy (HEA) produced by arc melting was processed by high-pressure torsion (HPT) at room temperature. Thermodynamic calculations and experimental results indicated a dual-phase microstructure composed of about 85% BCC Zr-depleted and 15% BCC Zr-rich phase in the as-cast condition. HPT causes grain refinement and an increase in dislocation density without the formation of new phases. After four revolutions, the Zr-depleted phase was hardened to $$\sim $$ ∼ 540 HV, while the Zr-rich phase exhibited softening with a decrease in hardness to $$\sim $$ ∼ 480 HV. The occurrence of a vortex-like microstructure and the analysis of elemental concentrations indicated a shear-induced mechanical homogenization, which was supposed to be the cause of the observed softening.

Influence of the Small Sc and Zr Additions on the As-Cast Microstructure of Al–Mg–Si Alloys with Excess Silicon

This research is devoted to the study effects of complex alloying of Al-0.3 wt.% Mg-1 wt.% Si and Al-0.5 wt.% Mg-1.3 wt.% Si alloys by small additions of Sc and Zr on the microstructure in the as-cast condition. The effect of small additions of these elements on the microhardness, electrical conductivity, grain size and phase composition of the indicated alloy systems was studied. The methods of optical and electron microscopy were used for the study. Moreover, the phase composition was calculated using the Thermo-Calc software package. The study showed a strong effect of the chemical composition of investigated alloys on the size of the grains, which, with a certain combination of additives, can decrease several times. Grain refinement occurs both due to supercooling and formation of primary Al3Sc particles in the liquid phase. Alloys based on Al-0.5 wt.% Mg-1.3 wt.% Si are more prone to the formation of this phase since a lower concentration of Sc is required for it to occur. In addition, more silicon interacts with other elements. At the same time, Al-0.3 wt.% Mg-1 wt.% Si requires lower temperature for complete dissolution of Mg2Si, which can contribute to more efficient heat treatment, which includes reducing the number of steps. TEM data show that during ingot cooling (AlSi)3ScZr dispersoid precipitates. This dispersoid could precipitate as coherent and semi-coherent particles with L12 structure as well as needle-shaped particles. The precipitation of coherent and semi-coherent particles during cooling of the ingot indicates that they can be obtained during subsequent multistage heat treatment. In addition, in the Al0,5Mg1,3Si0,3Sc alloy, metastable β’’ (Mg5Si6) are precipitated.

RHEINFELDEN CASTASIL-37

Rheinfelden Castasil-37 (AlSi9MnMoZr) is an aluminum-silicon-manganese-molybdenum-zirconium high pressure die casting (HPDC) alloy. It was developed by Rheinfelden Alloys GmbH for the production of large and complex high pressure die castings for automotive structural applications. This alloy is used in the as-cast condition, and exhibits good mechanical properties, especially elongation, which are superior to those of conventional aluminum-silicon alloys. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fatigue. It also includes information on corrosion resistance as well as casting, heat treating, and joining. Filing Code: Al-481. Producer or source: Rheinfelden Alloys GmbH & Co. KG.

Microstructural Evolution of Large Cast Haynes 282 at Elevated Temperature

Haynes 282 has attracted attention for casting applications in AUSC power plants due to its good creep properties. However, the market is primarily comprised of wrought Haynes 282, while the cast version is not commercially available. In this study, the microstructure of a large traditional sand cast Haynes 282 was studied from as-cast condition to long-term heat-treated condition by combining experimental data and thermodynamic calculations. The microstructure of a large cast Haynes 282 includes γ, γ’, two types of MX, M23C6 and µ phases. After standard post heat treatment, µ phases were dissolved and precipitated as M6C. The equilibrium state was achieved after 266 h aging at 788 °C, after which γ’ particles began coarsening. These kept to a spherical morphology; the smallest misfit was found with the γ matrix. Once post heat treatment was finished, MX exhibited little morphology and compositional change during the long-term isothermal aging. Grain boundary is covered by discrete M23C6 and M6C precipitates and this morphology keeps stable during isothermal aging. No presence of the needle µ phase have been found at grain boundaries after 10,000 h aging at 788 °C. All these microstructural features indicated that cast Haynes 282 could have a high thermal stability and good creep properties.

Effects of Hot Isostatic Pressing and Heat Treatment on the Microstructure and Mechanical Properties of Cast TiAl Alloy

Hot isostatic pressing (HIP) and subsequent heat-treatments (HT) are necessary for titanium aluminide (TiAl) casting components. But there are few studies carefully comparing the microstructure changes from the initial as-cast condition to the final heat-treated condition. In this study, the microstructures of Ti-47Al-2Cr-2Nb (at%) alloy in the as-cast, as-HIPed and as-heat-treated conditions were characterized by optical microscopy and scanning electron microscopy. The mechanical properties after HTs were determined by the tensile tests at 700 °C. The results show that after HIP and HTs, all the microstructures exhibit a nearly lamellar (NL) structure and can be divided into an edge region and a central area. The microstructure after HIP in the edge region is normal, while distorted lamellae and many fine recrystallized grains exist in the central area. The yield strengths after three HTs are nearly the same, but the elongation after the HT at 1310 °C is much more than that after HTs at 1185 °C and 1280 °C. A refinement of colony size induced by distorted lamellae in as-HIPed condition is considered responsible for the great improvement in elongation.

ALCOA 560

Alcoa 560 is a proprietary, non-heat-treatable, aluminum-magnesium-manganese alloy developed by Alcoa in the late 1990s for high pressure die cast structural components. This alloy develops the required strength and toughness in the as-cast condition, thus eliminating or minimizing numerous production problems, such as distortion, blistering, property variations, and heat treatment logistics. The application of this alloy is limited to simple-shaped components due to its high hot cracking tendency. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on corrosion resistance as well as casting and joining. Filing Code: Al-478. Producer or source: Alcoa Corporation.

Influence of magnesium on high-temperature structural-phase stability of Al-Ni-La system alloys

The paper considers a relevance of the Al-Ni-La system cast alloys development as promising materials for application at elevated temperatures. The influence of magnesium on the structural-phase characteristics of alloys-representatives with a nickel content of about 2% wt. and lanthanum - about 5,5 and 11,5% wt. were studied in the cast condition and after annealing at 425 ° C for 5 hours. It is shown, that the addition of magnesium in the amount of 0,6 wt%. to alloys with a lanthanum content of 5,5 % wt. helps to increase the size of the lanthanum-containing eutectic component in the cast state, but stimulates its grinding after annealing. Since doubling the lanthanum content, magnesium has almost no effect on the structure of the eutectic in the cast state, but intensifies the process of changing its structure during annealing. In this case, the size of the eutectic components is almost unchanged and can be compared with an undoped alloy. Increasing the magnesium content twice to 1,2% wt. in the alloy with a lanthanum content of 11% wt. leads to a noticeable enlargement of Al11La3 intermetallics. After annealing, this structural component retains the characteristics of a fibrous structure and at the same time increases in size by about half. The magnesium content in the eutectic zones and in the solid solution hardly changes after annealing. The obtained data indicate the possibility of using magnesium as an additional alloying element of cast heat-resistant alloys of the Al-Ni-La system, which is able to simultaneously contribute to their strengthening both under normal conditions and at elevated temperatures. In this case, magnesium, in the amount of about 0,6% wt., also helps to preserve the fine structure of the eutectic components at high temperatures. Keywords: Al-Ni-La, Al-Ni-La-Mg, alloying, structural stability, heat resistance.