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The analysis of strength and fracture morphology of Al-Si compound made from moulding sand formulation with bentonite binding material and Portland cement

Andoko F., Puspitasari P., Gapsari F.

Journal of Achievements in Materials and Manufacturing Engineering

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2018

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Vol. 89, nr 1

5--12

EN

Purpose: This research aimed to analyse the casting result of Al-Si compound used formulation of moulding sand with bentonite binding material and Portland cement. Design/methodology/approach: Bentonite binding material’s type consisted of swelling (Na-bentonite) and non-swelling (Ca-bentonite). Optimum formulation of the moulding sand was 4% of swelling bentonite and 6% of Portland cement, 6% of non-swelling bentonite and 4% of Portland cement. The optimum formulation result of molding sand with bentonite binding material and Portland cement was used in Al-Si compound casting. The result of Al-Si compound casting strength was examined which in terms of its tensile strength, toughness, and hardness. Besides the three tests, the result was also supported by the fracture shape morphology of tensile test and impact toughness test result. Based on the Al-Si compound tensile test result, it was found that the best value was obtained when using 105.52 MPa of swelling bentonite. Findings: The impact toughness test result presented that the use of non-swelling bentonite produced better toughness value which was 0.00592 J/hour while the mickroVickers hardness test result showed that Al-Si compound result using non-swelling bentonite produced 111.04 HV hardness. Based on the fracture morphology test result using SEM of Al-Si compound casting result using swelling and non-swelling bentonite after being tested its tensile strength and impact toughness showed that the same fracture which was brittle fracture tended to appear. Research limitations/implications: In this casting process, combination which is being used is bentonite (swelling and non-swelling) and Portland cement as mould sand binding material. Practical implications: The combination can be used to find the bentonite type that can produce binding material formula with high binding level which can minimize defects on the resulted casting products. Originality/value: In this study swelling and non-swelling bentonite mixed with certain level of Portland cement combination are used.

2

Influence of thermal activation on the changes of physical properties and structure of cobalt-based metallic glass

Spilka M., Griner S., Kania A.

Archives of Materials Science and Engineering

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2012

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Vol. 56, nr 2

61--68

EN

Purpose: In this paper the analysis of influence of heat treatment on the structure and properties of AMM type (Co70.5Fe2.5Mn2Mo1Si9B15) metallic glass was shown. Moreover the discussion of the changes of tensile strength, plasticity, cracking energy, remanence, coercive force, resistivity, crystallization effect and fracture morphology of alloy in “as quenched” state and hold at the temperature range of 100-400°C for 2 hours are presented. Design/methodology/approach: Tensile test and investigation of elementary cracking energy of amorphous ribbon carried out using the testing machine were performed. Plastic properties of examined material was studied by using of transverse bend test. Investigation of magnetic properties with annular method with 50 Hz field frequency was carried out. The alloy electrical resistivity was determined with resistance bridge. Fractography investigation after tensile test was made using scanning microscope. Findings: The investigations showed that for the analysed heat treatment temperature range of 100-400°C significant changes of physical properties, fracture morphology and alloy structure are observed. Research limitations/implications: Usage of metallic glasses is possible only in a narrow range of temperatures which does not lead to significant changes of properties or after proper heat treatment carried out in the aim of specified physical properties obtaining. Practical implications: Usage of metallic glasses depending on control and regulations of alloy properties changes with proper heat treatment. It is important the prediction of alloy properties changes during temperature changes and material using. Originality/value: In the article influence of thermal activation processes on structure changes and significant changes of mechanical and magnetic properties of cobalt-based metallic glass were presented.

3

Influence of geometry of rapidly solidified rods on properties of Fe-Co-based alloy

Lesz S., Griner S., Nowosielski R.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 41, nr 1-2

16-25

EN

Purpose: The main aim of the paper was investigation of influence of geometry of rapid solidified rods on properties (structure, fracture morphology, microhardness) of Fe36Co36B19Si5Nb4 alloy. Design/methodology/approach: The following experimental techniques were used: differential thermal analysis (DTA), scanning electron microscopy (SEM), light microscopy (LM), X-ray diffraction (XRD) method, Vickers microhardness. Findings: Changes of mechanical properties (microhardness) and different fracture morphology of rapidly solidified rods were presented. Research limitations/implications: Obtained structures are depended on cooling rate and glass forming ability of the alloy. Practical implications: The rapidly solidified bulk alloys have been commercialized in magnetic application and high strength materials. Originality/value: Diverse fracture morphology as well as changes of microhardness in amorphous regions of differently relaxated rate are observed.