Effects of modification techniques on mechanical properties of Al-Si cast alloys
- Authors: Ebhota, Williams S. , Jen, Tien-Chen
- Date: 2017
- Subjects: Aluminium , Al‐Si alloys , Refinement
- Language: English
- Type: Book Chapter
- Identifier: http://hdl.handle.net/10210/244729 , uj:25310 , Citation: Ebhota, W.S. & Jen, T.C. 2017. Effects of modification techniques on mechanical properties of Al-Si cast alloys.
- Description: Abstract: Mechanical, physical and chemical properties of a part depend on the size, morphology and dispersion of the constituents of the microstructure of the part’s material. Therefore, this chapter discusses the different processes of altering the microstructure of Al‐Si based alloys to desired functional properties. These processes, commonly called modification methods, were broadly categorised into three: chemical, thermal and mechanical methods. Chemical method, which involves the addition of some elements, in trace levels, to alloys to be modified, is the best modification option. The elements for modifying are called modifiers. The three commonest used modifiers (sodium, Na, strontium, Sr and antimony, Sb) were discussed. The chapter, however, noted that for optimal alloy’s mechanical attributes, thermal treatment is usually combined with both chemical and mechanical modification processes. Thermal involves rapid cooling of alloy for modification, while mechanical method depends on force to break up large α‐Al dendrites and plate‐like Si phases.
- Full Text:
Numerical analysis of the cold gas dynamic spray surface coating process
- Authors: Moonga, Kando Hamiyanze , Jen, Tien-Chen
- Date: 2017
- Subjects: Cold spray , Numerical analysis , Multiple particle impact
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/243771 , uj:25199 , Citation: Moonga, K.H & Jen, T.C. 2017. Numerical analysis of the cold gas dynamic spray surface coating process. Advances in Engineering Research (AER), volume 102, Second International Conference on Mechanics, Materials and Structural Engineering (ICMMSE 2017).
- Description: Abstract: In Cold Spray, bonding is formed between substrate and the particles and between particles by impact which causes material deformation and temperature rise. During impact process, plastic deformation and frictional interaction of materials generate heat and strains/stresses. In this paper, a numerical study on multiple particles deposition process show that the plastic equivalent strain (von misses stress) and the temperature values, compare to a single particle impact under same conditions, are higher in multiple particles compared to a single particle impact. Based on this observation, there is a possibility of the bonding mechanism for the whole film coating better explained using the multiple particles modeling than is predicted using single particle analysis However the actual impacting mechanism in the multiple particle interaction is not yet fully understood and still requires further investigation.
- Full Text: