Microstructure and elevated temperature mechanical properties of Mg-6Gd-3Y-0.5Zr alloy cast by PEP–SET sand mold

The present work cast a complex Mg-6Gd-3Y-0.5Zr alloy component in a polybenzylic ether phenolic resin (PEP-SET) sand mold using by differential pressure casting. Microstructural characterization was carried out on the castings in the states of as-cast, solution treatment and aging treatment. Their mechanical properties were examined at elevated temperatures. The studied Mg alloy showed noticeably high tensile strengths up to 473 K, followed by a significant decrease with further increasing the testing temperatures. Its mechanical properties at elevated temperatures were compared with those of WE43 alloy fabricated under identical casting conditions.

A Comparative Analysis on Organic and Inorganic Core Binders for a Gravity Diecasting Al Alloy Component

The last two decades have seen a growing trend toward the use of inorganic binders in core making for the metalcasting field. Despite the health and environmental benefits of the inorganic binders, wider commercial use requires ongoing technical improvements to address some potential inherent limitations of this technology. Considering that inorganic cores can suffer from storage stability, this study sets out to check whether inorganic core binders are fit to replace organic ones in producing a gravity diecasting Al alloy component. First, the humidity resistance of both organic and inorganic sand cores, within a typical time-frame storage in the foundry, was evaluated by moisture absorption tests. Then, 3D optical measurements were performed to assess the relative dimensional changes of inorganic cores. Last, the influence of the core system was analyzed through microstructural and mechanical investigations on castings manufactured by using organic and inorganic binders. The experimental findings have shown that the moisture absorption during storage in the foundry warehouse, which lasted up to 14 days, was not enough to jeopardize the functionality of the cores. Furthermore, the tensile and microstructural outcomes revealed that inorganic cores could comply with both high component design requirements and even more stringent environmental regulations of foundries.

Deformation Characteristics and Microstructure Analysis of Aluminum Alloy Component with Complex Shape by Cold Orbital Forming

This work aimed to study the deformation characteristics and microstructure of AA6063 aluminum alloy component with complex shape manufactured by cold orbital forming processing. The material flowing behavior was analyzed by Finite Element (FE) simulation and forming experiments were carried out using bar blank with different lengths. The microstructure of the boss zone cut from the formed samples was observed using scanning electron microscopy (SEM) and electron back-scatter diffraction (EBSD). FE simulation and experiment results both showed the aluminum base can be formed using cold orbital forming process. The distributions of the effective strain of the component with different blank lengths were almost the same, and the effective strain was bigger at the boss and the flash as the forming finished. The material flow is complex, especially in the boss, and the folding defect was observed at the root of the boss. The distribution of Mg2Si strengthening precipitate is more homogeneous in the matrix, has a different shape, and shows directivity at different position of boss zone. The grains are elongated, and the extent is different at different positions of the boss zone after cold orbital forming, and the crystal orientation discrepancy is smaller in the component main body and bigger in the boss zone. Subsequent forming process and blank optimization need to be further researched to improve forming quality.

Forging Process Design and Simulation Optimization of a Complex-Shaped Aluminium Alloy Component

In order to meet the requirements of lightweight and replace steel with the aluminum for a component on the high speed rail, the forging process of a complex-shaped aluminum alloy component was researched and the parameters were optimized with the DEFORM-3D finite element simulation technology. The qualified products were finally obtained instead of the original steel castings by reducing weight of 65%. It is noted that the parts with complicated shape and non-symmetry, metal flow uneven during forging process that lead to incomplete forming, higher forging pressure problems. In this paper, such problems were analyzed couple with numerical simulation method based on a certain forming pressure. Moreover, the model and slot was reasonably designed. In addition, the size of blank was constantly optimized to change the metal flows direction and cavity filling mode. Finally, the forgings with good surface quality and mechanical properties were obtained by production test, and can be used as reference for this kind of forging components.