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Abstract

In this work, 25 wheels were cast with three different grain refiners: Al5Ti1B, Al3Nb1B and MTS 1582. Samples were machined from the wheels to check the mechanical properties. It was found that Nb grain refinement had the lowest grain size (260 mm) and highest tensile properties (yield strength of 119-124 MPa and ultimate tensile strength of 190-209 MPa). Al5Ti1B and MTS 1582 revealed quite similar results (110 MPa yield and 198 MPa ultimate tensile strength). The fading of the grain refining effect of Al5TiB1 master alloy was observed in both Nb and Ti added castings whereas during the investigated time interval, the fading was not observed when MTS 1582 was used.
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Authors and Affiliations

F. Aydogan
1
K.C. Dizdar
2
ORCID: ORCID
H. Sahin
2
ORCID: ORCID
E. Mentese
1
D. Dispinar
2
ORCID: ORCID

  1. Doktas Wheels, Turkey
  2. Istanbul Technical University, Turkey
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Abstract

Production of the defect-free casting of aluminium alloys is the biggest challenge. Porosity is known to be the most important defect. Therefore, many cast parts are subjected to several non-destructive tests in order to check their acceptability. There are several standards, yet, the acceptance limit of porosity size and distribution may change according to the customer design and requirements. In this work, the aim was targeted to evaluate the effect of size, location, and distribution of pores on the tensile properties of cast A356 alloy. ANSYS software was used to perform stress analysis where the pore sizes were changed between 0.05 mm to 3 mm by 0.05 mm increments. Additionally, pore number was changed from 1 to 5 where they were placed at different locations in the test bar. Finally, bifilms were placed inside the pore at different sizes and orientations. The stress generated along the pores was recorded and compared with the fracture stress of the A356 alloy. It was found that as the bifilm size was getting smaller, their effect on tensile properties was lowered. On the other hand, as bifilms were larger, their orientation became the dominant factor in determining the fracture.
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Bibliography

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Authors and Affiliations

H. Sahin
1
ORCID: ORCID
M. Atik
1
F. Tezer
1
S. Temel
1
O. Aydin
1
O. Kesen
1
O. Gursoy
2
D. Dispinar
3
ORCID: ORCID

  1. Istanbul Technical University, Turkey
  2. University of Padova, Italy
  3. Foseco, Netherlands
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Abstract

Casting is the most economical way of producing parts for many industries ranging from automotive, aerospace to construction towards small appliances in many shares. One of the challenges is the achievement of defect-free cast parts. There are many ways to do this which starts with calculation and design of proper runner system with correct size and number of feeders. The first rule suggests starting with clean melt. Yet, rejected parts can still be found. Although depending on the requirement from the parts, some defects can be tolerated, but in critical applications, it is crucial that no defect should exist that would deteriorate the performance of the part. Several methods exist on the foundry floor to detect these defects. Functional safety criteria, for example, are a must for today's automotive industry. These are not compromised under any circumstances. In this study, based on the D-FMEA (Design Failure Mode and Effect Analysis) study of a functional safety criterion against fuel leakage, one 1.4308 cast steel function block, which brazed-on fuel rail port in fuel injection unit, was investigated. Porosity, buckling, inclusion and detection for leak were carried out by non-destructive test (NDT) methods. It was found that the best practice was the CT-Scan (Computed Tomography) for such applications.
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Bibliography

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Authors and Affiliations

K.C. Dizdar
1
ORCID: ORCID
H. Sahin
1
ORCID: ORCID
M. Ardicli
2
D. Dispinar
3
ORCID: ORCID

  1. Istanbul Technical University, Turkey
  2. Bosch Powertrain Solutions, Bursa, Turkey
  3. Foseco Non-Ferrous Metal Treatment, Netherlands
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Abstract

Aluminum and its alloys are one of the most favored metal-based materials for engineering applications that require lightweight materials. On the other hand, composites are getting more preferable for different kinds of applications recently. Boron nitride nanotubes (BNNTs) are one of the excellent reinforcement materials for aluminum and its alloys. To enhance mechanical properties of aluminum, BNNTs can be added with different processes. BNNT reinforced aluminum matrix composites also demonstrate extraordinary radiation shielding properties. This study consists of BNNT reinforced aluminum matrix composite production performed by casting method. Since wetting of BNNT in liquid aluminum is an obstacle for casting, various casting techniques were performed to distribute homogeneously in liquid aluminum. Different methods were investigated in an aim to incorporate BNNT into liquid method as reinforcement. It was found that UTS was increased by 20% and elongation at fracture was increased by 170% when BNNT was preheated at 800°C for 30 minutes.
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Authors and Affiliations

B. Nemutlu
1
ORCID: ORCID
O. Kahraman
1
ORCID: ORCID
K. B. Demirel
1
ORCID: ORCID
I. Erkul
1
ORCID: ORCID
M. Cicek
1
ORCID: ORCID
H. Sahin
1
ORCID: ORCID
K.C. Dizdar
1
ORCID: ORCID
D. Dispinar
1
ORCID: ORCID

  1. Istanbul Technical University, Turkey

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