Thixoforming of an automotive part in A390 hypereutectic Al–Si alloy

In-Situ Si/Al Composite Produced by Semisolid Metal Processing

“…The precipitation of primary aluminium phase is not uncommon in Si-rich alloys and is usually explained in terms of eutectic growth switching from the liquidus extension on one side of the eutectic coupled zone to the other, driven by nucleation difficulties and solute build-up. The coexistence of both silicon and aluminium phases in a primary form has also been reported by Arnberg et al [8] and Kapranos et al [2]. During the partial remelting and isothermal holding, the primary silicon particles remain solid, so the size and morphology of silicon particle need to be carefully controlled in the ascast stage.…”

“…They combine the beneficial properties of the metal matrix, such as good ductility, good thermal and electrical conductivity, and high toughness, with the properties of the silicon reinforcing phase, such as high wear resistance, high yield strength and low thermal expansion. The materials have attracted increasing interest in automotive applications, especially in heavy wear components, such as pistons, cylinder blocks, pump bodies and compressors [1,2]. However, their use has always been tempered by several difficulties, in particular, their high latent heat and consequent long solidification time resulting in die wear, and difficulty in controlling the size and distribution of the primary Si phase [3].…”

“…Moreover, using semisolid casting, the casting temperature and heat content are very much reduced, which results to less die wear and total shrinkage. Production of hypereutectic Al-Si alloy with small primary silicon particles has been reported using electromagnetic stirring [2], mechanical stirring [6] and ultrasonic treatment [7]. This paper presents the results of producing in-situ Si/Al composite by semisolid metal processing.…”

Wear properties of thixoformed AlSiCuFe alloys

“…High wear resistance, high strength, high hardness, low thermal expansion and reduced density make hypereutectic Al-Si alloys very competitive for this demanding application [1,2]. However, the use of conventionally cast hypereutectic Al-Si alloys has been restricted owing to their high latent heat and consequent long solidification time which results in die wear, segregation and excessive growth of primary silicon particles, and unfavourable shrinkage behaviour [3]. Since the casting temperature and heat content are relatively lower, the primary silicon is finer and uniformly distributed and the shrinkage is much less than that of a molten alloy, thixoforming may be a viable alternative to die casting.…”

Structural Properties and Mechanical Behavior of the 2 Step-Reinforced Al-Si/SiCp Metal Matrix Composite by Titanium-Fiber

“…Aluminum (Al) and its alloys due to low density, highspecific strength, remarkable malleability, excellent castability and high corrosion resistance have been rapidly required and developed for the continued growth in automotive industry [1][2][3]. In addition, these materials in use are produced by inexpensive manufacturing process is essential for mass production as like casting and powder metallurgy (PM) process [4][5][6][7].…”