Permanent Mold Casting Research Articles

Microstructure-dependent thermal conductivity and mechanical properties in cast Mg-4Sm-xAl alloys

The thermal conductivity of Mg-Sm binary alloys is relatively poor due to the severe lattice distortion introduced by the high solid solubility Sm atom in the Mg matrix, which restricts their widespread application. In this study, the viability of Al alloying (0–2.6 wt%) in permanent mold cast Mg-4Sm (wt.%) alloy was investigated to design cast Mg alloys with high thermal conductivity. It is found that the thermal conductivity significantly improved with the addition of Al content, and peaked at 136.8 W/(m·K) with an Al content of 1.5 wt%, which is attributed to the release of the Sm atoms from the Mg matrix. It is also confirmed that minimizing the lattice distortion effect is critical to achieving high thermal conductivity. The formation of Al2Sm and Al11Sm3 phases leads to a dramatic decline in solid solution strengthening due to its strong consumption of the dissolved Sm atoms, but in the meantime enhances secondary phase strengthening and promotes stronger interactions between different strengthening components. The optimum combination of mechanical properties and thermal conductivity is obtained in Mg-4Sm-2Al alloy, which possesses a yield strength of 102.6 MPa, elongation of 6.8% and thermal conductivity of 124.5 W/(m·K), compared with several commercial as-cast Mg alloys.

Hot tearing and mechanical properties of high electrical and thermal conductivity Al-Fe-Mg-Si-Ni Alloys

ABSTRACT Aluminium alloys with Fe and Ni show potential as high castability alloys with high strength and high electrical/thermal conductivities for electric vehicle powertrains. Permanent mould castings of Al-Fe-Ni alloys with additions of Mg and Si were prepared to assess hot tearing susceptibility and mechanical properties. The electrical conductivity of the Al-Fe-Ni alloys was measured, and the Wiedemann-Franz law was used to estimate the thermal conductivity. The results show that a hot tear resistant Al-Fe-Ni alloy with composition Al-1.2Fe-0.5Mg-0.3Si-0.2Ni had an electrical conductivity of 50.91 ±0.29%IACS with yield strength, ultimate tensile strength, and elongation of 60.5 MPa, 141 MPa and 7.9%, respectively. The microstructure of the Al-Fe-Ni alloys contained primary Al, Al9FeNi and Mg2Si. The short freezing ranges and fine intermetallics allowed for good castability. The prepared Al-Fe-Ni alloys are potential new castable Al alloys that have thermal and electrical conductivity nearing wrought (6061 and 6101) compositions.

Mechanical properties and microstructure of a high-quality Mg-Nd alloy ingot with large size manufactured by direct chill casting

In this work, a high-quality Mg-2.85Nd-0.25Zn-0.5Zr (wt%) alloy ingot with a diameter of 280 mm was successfully fabricated by direct chill casting. There was no obvious composition segregation along the radial direction of the ingot. The large temperature gradient along the radial direction, accurately the higher cooling rate in the surface, gives rise to both grain size and eutectic compounds fraction to gradually decrease from the center to the surface. This results in varying mechanical properties at different positions, such as higher strength and ductility in the surface than in other positions. The peak-aged alloy exhibited a higher strength-ductility synergy, with tensile strength of 282 MPa and elongation of 12.5%, than other Mg-Nd based alloys processed by permanent mold casting and sand casting. Furthermore, it is worth noting that the peak-aged alloy manifested significant strain hardening and high heat resistance, as evidenced by liner strain hardening at temperatures between 100 and 250 °C, which is mostly due to stable solute hardening triggered by the large atomic radius of Nd atoms in the α-Mg matrix. These findings provide references for the application and manufacture of large-scale magnesium alloy ingots. • A high-quality Mg-2.85Nd-0.25Zn-0.5Zr (wt%) alloy ingot with a diameter of 280 mm was successfully fabricated by direct chill casting. • The fraction of eutectic compounds increases and the grain size decreases from the center to the surface. • The alloy exhibited higher strength-ductility synergy than other Mg-Nd based alloys processed by permanent mold casting and sand casting. • The alloy showed abnormal strain hardening at high temperatures, rather than strain softening.

RAFFMETAL EN AB-Al Si10Mg (EN AB-43000)

Abstract RAFFMETAL EN AB-Al Si10Mg (EN AB-43000) is a heat-treatable, aluminum-silicon-magnesium casting alloy in ingot form for remelting. It is used extensively for producing sand and permanent mold castings for applications requiring a combination of excellent casting characteristics, high strength with fair elongation, and fair corrosion resistance. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on casting, heat treating, machining, and joining. Filing Code: Al-491. Producer or source: Raffmetal S.p.A.

RIO TINTO C355.2

Abstract Rio Tinto C355.2 is a heat-treatable, aluminum-silicon-copper-magnesium casting alloy (3xx.x series). It is available in the form of ingots for remelting, to be used for the production of sand and permanent mold castings. Alloy C355.0 is a higher purity, low iron version of alloy 355.0. Both the alloys are similar, except the lower iron in C355.0 provides better elongation and somewhat higher tensile strength. Alloy C355.0 is used in premium, high strength applications where castings are usually heat treated for maximum strength. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Al-490. Producer or source: Rio Tinto Limited.

Microstructure and impact behavior of Mg-4Al-5RE-xGd cast magnesium alloys

This work investigated the microstructure and impact behavior of Mg-4Al-5RE-xGd (RE represents La-Ce mischmetal; x = 0, 0.2, 0.7 wt.%) alloys cast by high-pressure die casting (HPDC), permanent mold casting (PMC), and sand casting (SC) techniques. The results indicated that with increasing Gd content, the grain sizes of the HPDC alloy had a slight change, but the grains of the PMC and SC alloys were significantly refined. Besides, the acicular Al11RE3 phase was modified into the short-rod shape under the three casting conditions. The impact toughness of the studied alloy was mainly dominated by the absorbed energy during the crack initiation. With increasing Gd content, the impact toughness of the studied alloy monotonically increased due to the lower tendency of the modified second phase toward crack initiation. The impact stress was higher than the tensile stress, exhibiting a strain rate sensitivity for the mechanical response; however, the HPDC alloy had an inconsistent strain rate sensitivity during the impact event due to the transformation of the deformation mechanism from twinning to slip with increasing strain. Abundant dimples covered the fracture surface of the fine-grained HPDC alloys, indicating a typical ductile fracture. Nevertheless, due to the deficient {101¯2} twinning activity and the suppressed grain boundary sliding during the impact event, the HPDC alloys showed insufficient plastic deformation capacity.

Effect of Zn content on microstructure and properties of hypoeutectic and near-eutectic Al-Si alloys

In this research, the microstructure and mechanical properties of permanent mould cast Al-Si (7 wt.% and 12 wt.%) alloys without and with different amounts of Zn (1 wt.%, 2 wt.% and 4 wt.%) were analysed. The Al-xSi-yZn alloys have been prepared through a stir casting process using an Al-15 wt.% Si master alloy at 800 °C. Optical microscopic analyses have revealed variation in the α-Al matrix and Si needles in the alloy with the variation in Zn content. The mechanical properties analysis has shown that the hardness, tensile strength and wear resistance of the alloys increase with the addition of Si but decrease with the addition of Zn, within the limit of the alloying additions of the present research.

Production of filler rods for repair welding of ML12 (ZK51) magnesium alloy castings

In magnesium alloys castings, the casting defects such as shrinkage porosity are often occur. Such defects can be suppressed by repair welding or surfacing using a special filler rod. Unfortunately, in Russia, the low amount of filler rod is consumed. Therefore, native enterprises do not manufacture it, limiting themselves to imports or homemade low-quality substitutes. Nevertheless, there is a need for filler rod, and recently it has become unprofitable to replace them with imported materials due to a significantly increased price. Therefore, there is a need to study the technology of its production to replace imported filler rod with native material. Magnesium alloys based on the Mg–Zn–Zr (La, Nd) system: SV1, SV122, and ML12 (ZK51) that used as a filler rod for repair welding of ZK51 alloy castings were studied in this work. The samples were obtained by permanent mold casting into aluminum molds followed by hot extrusion into a filler rod with a diameter of 4 mm. It was shown that all the investigated alloys could be obtained in the form of a rod with a diameter of 4 mm. Therefore, the investigated rod samples from the SV122 alloy were used as filler material for repair welding of ZK51 magnesium alloy castings. The weld seam in the T1 condition has an ultimate tensile strength (UTS) about 80 % of the UTS of the casting material.

Investigation of the effect of the addition of grain refiner and modifier addition on wear properties in sand and permanent mould casting of A357 and A380 aluminium alloys

ABSTRACT The aim of this study is to improve the tribological behaviour of aluminium alloys by using grain refiner and modifier. The effects of Al5Ti1B grain refiner and Al10Sr modifier additives on friction and wear properties on A380, A357 alloys produced by pouring sand andpermanent mould casting were investigated. Abrasion tests were carried out under dry conditions against St1040 steel disc using a pin-disk system with 20 N load and 1.0 m/s sliding speed. It was determined that grain refiner and modifier additives decrease the friction coefficient and increase the wear resistance. It was determined that the samples produced by permanent mould casting method decreased the friction resistance by 9% and the abrasion resistance increased by 40% compared to the samples produced in sand mould. The lowest wear rate was obtained in A380 alloy with TiB and Sr added with a value of 4.87 × 10–11 m2/N.

Experimental research on machinability characteristics of Al-9Si alloy: Effect of Sr and Mg additives

In this study, the effects of strontium (Sr) and magnesium (Mg) elements in certain rates added to Al-9Si alloy manufactured using permanent mold casting technique on the structural, mechanical, and machinability properties of these alloys were investigated. While microstructural images of the alloys were obtained with an optical microscope, hardness, tensile strength, and elongation to fracture were determined by conventional methods. The resultant cutting force ( F) and average surface roughness ( Ra) were measured as experimental outputs in the turning process. It was observed that Al-9Si alloy comprised of α-Al, eutectic Al-Si, β, and primary Si phases. The addition of Sr to the Al-9Si alloy led to the formation of the Al4Sr phase and the transformation of the β phase into the δ phase. The addition of Mg to Al-9Si-0.1Sr alloy caused the δ phase to transform into the π phase. The hardness of the tested alloy increased significantly with the Mg addition. The yield strength and tensile strength of them increased with both Sr and Mg additions. On the other hand, elongation to fracture value of the Al-9Si alloy increased with Sr addition while it decreased with the Mg addition. The F and Ra values obtained from the Al-9Si alloy increased with Sr addition in the turning process while decreased with Mg addition. The results obtained from turning tests were discussed based on the mechanical properties of alloys.

RIO TINTO 355.2

Abstract Rio Tinto 355.2 is a heat-treatable, aluminum-silicon-copper-magnesium casting alloy (3xx.x series). It is available in the form of ingots for remelting, for the production of sand and permanent mold castings. It is a high-strength alloy with many desirable characteristics. The presence of copper in alloy 355.0 increases strength but reduces corrosion resistance and ductility. This alloy is less ductile than 356.0. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Al-486. Producer or source: Rio Tinto.

Tool development for hybrid finishing milling of iron aluminides

The importance of high-temperature materials made of iron aluminides (FeAl) has been increasing in light weight applications, e.g., airplane turbines, due to the high material’s specific strength. However, the highly economic production by means of permanent mold casting involves special microstructures for Fe26Al4Mo0.5Ti1B alloy components leading to difficult machinability for subsequent finishing milling and low surface qualities. Major effects of tool and machining parameter variation incorporating ultrasonic assistance on the milling process and surface integrity are shown. Loads for tool and component surface are significantly adjustable to enable an economic process chain regarding the surface integrity of safety-relevant components.

RAFFMETAL EN AB-Al Si7Mg0.6 (EN AB-42200)

Abstract Raffmetal EN AB-Al Si7Mg0.6 (EN AB-42200) is a heat-treatable, Al-Si-Mg casting alloy in ingot form for remelting. It is used extensively for producing sand, permanent mold, and investment castings for applications requiring a combination of excellent casting characteristics, high strength with good elongation, and good corrosion resistance. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Al-483. Producer or source: Raffmetal S.p.A.

Microstructure and Phase Formation of Novel Al80Mg5Sn5Zn5X5 Light-Weight Complex Concentrated Aluminum Alloys

In this work, three novel complex concentrated aluminum alloys were developed. To investigate the unexplored region of the multicomponent phase diagrams, thermo-physical parameters and the CALPHAD method were used to understand the phase formation of the Al80Mg5Sn5Zn5Ni5, Al80Mg5Sn5Zn5Mn5, and Al80Mg5Sn5Zn5Ti5 alloys. The ingots of the alloys were manufactured by a gravity permanent mold casting process, avoiding the use of expensive, dangerous, or scarce alloying elements. The microstructural evolution as a function of the variable element (Ni, Mn, or Ti) was studied by means of different microstructural characterization techniques. The hardness and compressive strength of the as-cast alloys at room temperature were studied and correlated with the previously characterized microstructures. All the alloys showed multiphase microstructures with major α-Al dendritic matrix reinforced with secondary phases. In terms of mechanical properties, the developed alloys exhibited a high compression yield strength up to 420 MPa, high compression fracture strength up to 563 MPa, and elongation greater than 12%.

Mould design optimisation by FEM

Production can be briefly defined as creating something new as a result of effort. There are many different production methods. With the industrial revolutions, the number of these methods has increased, and these methods have developed. Over time, heavy and laborious work that people had to do began to be done by machines. The casting method, which is one of the most common production methods in the world, is to pour the molten metal or its alloy into a mould cavity suitable for the shape of the desired product and remove it from the mould after it solidifies. In this study, firstly, the manufacturing method by casting was mentioned, and the difficulties of mould design in the casting method were explained. Secondly, the benefits of computer-aided simulation programs for casting are explained. As an example, a model was designed and different runners were added to this model. These models, which were prepared afterwards, were cast in a virtual environment with the FLOW-3D CAST program, which is a simulation program. Casting results and casting defects after these castings were compared and interpreted. The results show that it is important for the casting quality to keep the runner diameters as small as possible in runner designs. Two or three times more air voids are formed in the sand mould casting method compared to the permanent mould casting. Additionally, it was observed that the casting material had less shrinkage in the sand mould casting method. It is concluded that sand mould casting is disadvantageous in terms of the parameter of time.

Effects of Eu modification and heat treatment on microstructure and mechanical properties of hypereutectic Al–Mg2Si composites

To modify the coarse primary Mg2Si phase and improve mechanical properties of Mg2Si reinforced aluminum matrix composites, hypereutectic Al–18Mg2Si composites with different Eu contents were fabricated by permanent mold casting and extrusion followed by heat treatment. Results show that the as-cast Al–18Mg2Si composites consisted of primary Mg2Si and eutectic structure (Al + Mg2Si). Eu addition can obviously modify the primary Mg2Si morphology from dendrite to flat truncated octahedron shape, and the average size also decreased from ∼90 μm to ∼16 μm with increasing Eu content from 0 to 0.1%. But further increasing Eu content would cause over-modification. After T6 treatment, sharp corners of primary Mg2Si were spheroidized and the average size of primary Mg2Si were further decreased. DTA result shows the nucleation temperature of primary Mg2Si increased by Eu addition. Al2Si2Eu phase can act as the heterogeneous nucleation substrate for the primary Mg2Si phase and thus refine the size of primary Mg2Si particle. TEM results show the segregation and/or selective adsorption of Eu on the {100} facets of primary Mg2Si suppress the growth of primary Mg2Si, and thus refine and modify the composites, which proposed to the dominant reason for the refinement and modification of the primary Mg2Si phase. Tensile tests show that the mechanical properties enhanced with increasing Eu content. The elongation and ultimate tensile strength of the T6-treated Al–18Mg2Si-0.1Eu composite improved to 5.2% and 241 MPa, which enhanced 225% and 91% compared to the unmodified as-cast Al–18%Mg2Si composite. It is concluded that the morphology transition of primary Mg2Si from dendrite to tetrakaidecahedron and the refinement of primary Mg2Si size with Eu modification, the passivation of the sharp corners in primary Mg2Si particles as well as the appearance of β" precipitates all contribute to the improvement of the mechanical properties of the T6-treated Al–18Mg2Si composites.

RAFFMETAL EN AB-Al Si7Mg0.3 (EN AB-42100)

Abstract Raffmetal EN AB-Al Si7Mg0.3 (EN AB-42100) is a heat-treatable, Al-Si-Mg casting alloy in ingot form for remelting. It is used extensively for producing sand, permanent mold and investment castings for applications requiring a combination of excellent casting characteristics, high strength with good elongation, and good corrosion resistance. This alloy can be produced to a wide range of mechanical properties by making small adjustments to the magnesium content and/or heat treatment. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Al-480. Producer or source: Raffmetal S.p.A.

Evaluating the Application of Heating Conductor Surfaces Inside Plasma Sprayed Coatings in Permanent Mold Metal Casting Processes for Local, Near-Surface Heat Release

With casting being a complex process which involves several physical effects and interactions, a wide array of means for influencing such processes exist. Here, the liquid–solid phase change is of utmost importance, as it is a deciding factor for a part’s final properties. Especially with today’s high critical material property requirements, control of the solidification process is indispensable. For the most part, the cooling of a casting defines its solidification. What determines the cooling process is the heat balance of the system. The foundry industry has been using different approaches for influencing the heat balance for a long time. The application of different kinds of coatings with either insulating or heat transfer promoting properties as well as temperature control via cooling channels inside the mold is widely used. Progress in the field of plasma spraying of coatings and the application of heating conductor surfaces have rendered a new concept possible: The integration of heating conductors inside a coating allows for the release of heat in closest vicinity of the melt–mold interface. This paper depicts the use of numerical simulations to investigate the local application of heating conductor layers inside the mold surface coating for a permanent mold casting process and discusses concepts for influencing the heat balance that would not be possible with state-of-the-art cooling channel approaches.

Influence of Mg addition and T6 heat treatment on microstructure, mechanical and tribological properties of Al–12Si–3Cu based alloy

The aim of the present study was to investigate the influence of Mg addition and T6 heat treatment on microstructure, mechanical and tribological properties of the Al–Si–Cu–Mg alloys. In this context, a series of Al–12Si–3Cu–(0.5–2.5)Mg (wt.%) alloys were produced by permanent mould casting, and then subjected to T6 treatment. Their microstructure and mechanical properties were investigated using OM, XRD, SEM, EDS along with hardness, tension, compression and Charpy impact tests. Dry sliding friction and wear properties of the alloys were studied using a ball-on-disk type tester. It was observed that the microstructure of as-cast Al–12Si–3Cu–Mg alloys consisted of α(Al), Si, θ-CuAl2, β-Mg2Si, Q-Al5Mg8Cu2Si6 and π-Al8Mg3FeSi6 phases. T6 heat treatment gave rise to nearly spherodization of eutectic Si particles, formation of finer θ-CuAl2 and β-Mg2Si precipitates and elimination of Chinese script morphology of β-Mg2Si phase. The addition of Mg up to 2.5 wt.% decreased the hardness, tensile and compressive strengths, tensile elongation and impact toughness of the as-cast and T6-treated alloys and increased their friction coefficient and volume loss. T6 treatment, on the other hand, led to a significant increase in mechanical properties and wear resistance of as-cast alloys.

RIO TINTO 354.2

Abstract Rio Tinto 354.2 is a heat-treatable, aluminum-silicon-copper-magnesium casting alloy (3xx.x series). It is available in the form of ingots for remelting to be used for the production of sand and permanent mold castings. Alloy 354.0 was developed especially for premium engineered casting applications requiring high strength and elongation, and sound castings. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on corrosion resistance as well as casting and heat treating. Filing Code: Al-479. Producer or source: Rio Tinto Limited.