This study used high-speed synchrotron X-ray tomography to image the growth of Al2Cu intermetallic compounds in 4D (3D plus time) during solidification Al-45wt%Cu alloy. Two categories patterns (basic units and dendrites) are identified. Basic elongated rods whose cross-section L, U or hollow-rectangular shapes. The transition from L pattern finally shaped morphology is observed. Faceted dendri...

All metals and alloys with exception of Bi are shrinking during cooling, mostly during the solidification process. In order to avoid shrinking porosity, casting process, and gating and feeding system must be properly designed. Solidification front must move towards the feeding system where solidification is then completed. No separate liquid pockets where solidification ended without feeding sh...

Solidification is a key step in additive manufacturing technology because it determines the microstructure and performance of final product. Our work provides nanoscale description relevant solidification processes for polycrystalline Ni by means molecular dynamics simulations. In particular, we focus on thermal effects associated with characteristic non-stationary conditions manufacturing. Dir...

Abstract A fundamental understanding of crystal growth dynamics during directional solidification multicrystalline Si (mc-Si) is crucial for the development technology mc-Si ingots use in solar cells. In situ observation crystal/melt interface a way to obtain direct evidence phenomena that occur at moving growth. this review, some occurring processes are introduced based on our experiments, aft...

The effects of Ta content (2.72wt.%, 3.10wt.% and 4.00wt.%) on the solidification characteristics mechanical properties directionally solidified DZ411 Ni-based superalloys were investigated. It is found that Mo decreases with increase in liquid phase after directional solidification, indicating addition can reduce element segregation alloys. primary secondary dendrite arm spacings (PDAS SDAS) a...

The physical and mechanical properties of an entirely (wrought alloys) or partly (cast dendritically solidified alloy strongly depend on the secondary dendrite arm spacing (SDAS). casting practice simulation solidification need a usable but simple method to calculate SDAS during at end as function cooling rate. Based many experiments, equation (empirical method) is known use local time, which c...

This paper presents a systematic procedure based on the adjoint method for solving a class of inverse directional alloy solidification design problems in which a desired growth velocity v f is achieved under stable growth conditions. To the best of our knowledge, this is the first time that a continuum adjoint formulation is proposed for the solution of an inverse problem with simultaneous heat...

A Rayleigh number based criterion is developed for predicting the formation of freckles in Ni-base superalloy castings. This criterion relies on finding the maximum local Rayleigh number in the mush, where the ratio of the driving buoyancy force to the retarding frictional force is the largest. A critical Rayleigh number for freckle formation of approximately 0.25 is found from available experi...