scholarly journals Scratch Testing of AlSi12/SiCp Composite Layer with High Share of Reinforcing Phase Formed in the Centrifugal Casting Process

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1685
Author(s):  
Anna Janina Dolata ◽  
Marek Mróz ◽  
Maciej Dyzia ◽  
Magdalena Jacek-Burek

The scratch test enables assessing the susceptibility of a material to the development of scratches and, being in some ways a measure of its abrasion resistance, allows extended knowledge in the field of material application usability, especially its machining capabilities. The aim of the study was to assess the resistance of a centrifugally formed AlSi12/SiCp composite layer with a high share of reinforcing phase (Vp > 40%) to scratching with a diamond indenter. The microstructure and effect of the load applied to the diamond indenter on the scratch depth and susceptibility of the composite layer to the nucleation and propagation of cracks in hard and brittle SiC particles were analyzed. A simple model of SiCp cracking depending on their size, shape (geometry), and orientation in relation to the direction of scratching has been proposed.

2018 ◽  
Vol 925 ◽  
pp. 318-325
Author(s):  
Rohollah Ghasemi ◽  
Anders E.W. Jarfors

The present study focuses on scratch behaviour of a conventional pearlitic and a number of solid solution strengthened ferritic Compacted Graphite Iron (CGI) alloys. This was done by employing a single-pass microscratch test using a sphero-conical diamond indenter under different constant normal loads conditions. Matrix solution hardening was made by alloying with different content of Si alloy; (3.66, 4.09 and 4.59 wt%. Si) which are named as low-Si, medium-Si and high-Si ferritic CGI alloys, respectively. A good correlation between the tensile and scratch test results was observed explaining the influence of CGI’s matrix characteristics on scratch behaviour both for pearlitic and fully ferritic solution strengthened ones. Both the scratch depth and scratch width showed strong tendency to increase with increasing the normal load, however the pearlitic one showed more profound deformation compared to the solution strengthened CGI alloys. Among the investigated alloys, the maximum and minimum scratch resistance was observed for high-Si ferritic CGI and pearlitic alloys, respectively. It was confirmed by the scratched surfaces analysed using Scanning Electron Microscopy (SEM) as well. In addition, the indenter’s depth of penetration value (scratch depth) was found as a suitable measure to ascertain the scratch resistance of CGI alloys.Keywords: Silicon solution strengthening, CGI, Abrasion, Scratch testing, Scratch resistance


2011 ◽  
Vol 117-119 ◽  
pp. 1610-1613
Author(s):  
Zhen Kai Zhao ◽  
Yan Pei Song ◽  
Zhi Ming Feng

The mathematical physical model of the unmelted WC particle distribution in the centrifugal force field was established in cylindrical coordinate system using continuity theory and hydromechanics. According to the migration rule of WC particle in the Fe-C alloy melt under centrifugal field, the mathematical equation of particle volume fraction distribution including centrifugal casting parameters was formulated. The mathematical equations were calculated by solving the mathematical equation with numerical analysis, and also the distribution regularity of WC particle in composite layer under different temperature and different Centrifugal speed was achieved. The results show that the particle reinforced composite with a gradient distribution along thickness was prepared by centrifugal casting. The gradient distribution of the particle changes with pouring temperature and centrifugal speed. And the theoretical data accord with experiment data compared to the experimental measurement.


Author(s):  
Williams S. Ebhota ◽  
Akhil S. Karun ◽  
Freddie L. Inambao

The study investigates the application of centrifugal casting process in the production of a complex shape component, Pelton turbine bucket. The bucket materials examined were functionally graded aluminium A356 alloy and A356-10%SiCp composite. A permanent mould for the casting of the bucket was designed with a Solidworks software and fabricated by the combination of CNC machining and welding. Oil hardening non-shrinking die steel (OHNS) was chosen for the mould material. The OHNS was heat treated and a hardness of 432 BHN was obtained. The mould was put into use, the buckets of A356 Alloy and A356-10%SiCp composite were cast, cut and machined into specimens. Some of the specimens were given T6 heat treatment and the specimens were prepared according to the designed investigations. The micrographs of A356-10%SiCp composite shows more concentration of SiCp particles at the inner periphery of the bucket. The maximum hardness of As-Cast A356 and A356-10%SiCp composite were 60 BRN and 95BRN respectively, recorded at the inner periphery of the bucket. And these values appreciated to 98BRN and 122BRN for A356 alloy and A356-10%SiCp composite respectively after heat treatment. The prediction curves of the ultimate tensile stress and yield tensile stress show the same trend as the hardness curves.


2015 ◽  
Vol 101 (9) ◽  
pp. 488-493 ◽  
Author(s):  
Hisao Esaka ◽  
Yoshimasa Kataoka ◽  
Kei Shinozuka

2010 ◽  
Vol 139-141 ◽  
pp. 557-560
Author(s):  
Wen Bin Sheng ◽  
Chun Xue Ma ◽  
Wan Li Gu

TiAl-based alloy valves were manufactured by combining charges compressed /vacuum arc melting (VA)/ induction skull melting (ISM) procedure with permanent mold centrifugal casting method. Microstructures, compositions and mechanical properties of as-cast and hot isostatical pressed (HIPed) valves are detected. Results show that the permanent mold centrifugal casting process obviously refines the size of grain in TiAl alloy and the tensile strength of as-cast and HIPed valves are 550MPa and 580MPa at 20°C, 370MPa and 470MPa at 815°C, respectively. As-cast specimens show ~0% elongation at 20°C and 1~2% at 815°C, while HIPed ones show an elongation of 1~2% at room temperature and about 10% at 815°C. Furthermore, a 200-hour test was carried out with CA4GE-engine, which demonstrated the possibility of as-cast TiAl alloy valves for the substitution of present steel ones.


Author(s):  
A.K. Nasution ◽  
D. Gustiani ◽  
A. Handoko ◽  
Mukhtar ◽  
Zulkarnain ◽  
...  

The high cost of health services in low-income countries has caused them to produce implants and medical devices at low cost. This research highlights a preliminary study of the design concept, mould design, and fabrication of horizontal type centrifugal casting machines for the manufacture of dynamic compression plates materials. Normally, dynamic compression plate is produced from materials such as 316L stainless steel, cobalt, and titanium alloys. In this work, aluminium-silicon alloy was used in this preliminary study. Aluminium-silicon alloy was melted at a temperature of 730 °C and poured into a mould with a rotational speed of 1500 rpm. Tensile, hardness and microstructure investigation were carried out to discern the mechanical properties of the cast product from the horizontal type centrifugal casting machine. Results showed the measured value of tensile strength is not significantly different in the two zones of cast pipe, the butt zone of fall of molten metal (specimen A) was 147 MPa, and the butt-end zone (specimen B) was 142 MPa. The hardness value for the as-cast pipe obtained from the outside, middle, and inside, was 104.0, 92.9, and 80.3 HV, respectively. Evaluation of microporosity in fractures (from tensile test) results from horizontal type centrifugal castings showed a small distribution. Meanwhile, the calculation of the contour hole processing time for DCP with eight holes is 38 minutes per implant.


1969 ◽  
Vol 21 (6) ◽  
pp. 607-612 ◽  
Author(s):  
James M. Fairchild ◽  
Ellsworth K. Kelly

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