Geometry Effect on Spark Erosion Behavior of Silver Matrix Composites

2003 ◽  
Vol 249 ◽  
pp. 183-188
Author(s):  
Shou Yi Chang ◽  
Liang-Yu Chou ◽  
Cher-Hao Hsu ◽  
Su Jien Lin
2003 ◽  
Vol 18 (4) ◽  
pp. 817-826 ◽  
Author(s):  
Chia-Jung Hsu ◽  
Shou-Yi Chang ◽  
Liang-Yu Chou ◽  
Su-Jien Lin

An electroless plating and hot-pressing process was developed to fabricate silver matrix composites reinforced with uniformly distributed graphite and Saffil short fibers (Graphitesf and Saffilsf). The hardness of the composites increases as the content of short fibers increase. Static-gap, single-spark erosion and repeated-collision, multiple-arc erosion tests were used to investigate the arc erosion behavior of the composites. The composites exhibited better arc erosion resistance when the contents of short fibers were increased in a static-gap, single-spark erosion test. However, the weight loss of the composites after 10,000 times repeated-collision, multiple-arc erosion operation shows that the composites with low volume percents of short fibers have a good arc erosion resistance. The Saffilsf/Ag composites show a better arc erosion resistance than Graphitesf/Ag because of the greater strengthening effect of the finer Saffil short fibers. The erosion behavior of the composites is dominated by the viscosity of composites in single-spark tests, while it depends on the competition of viscosity and thermal properties in multiple-arc tests.


2003 ◽  
Vol 18 (4) ◽  
pp. 804-816 ◽  
Author(s):  
Shou-Yi Chang ◽  
Chia-Jung Hsu ◽  
Cher-Hao Hsu ◽  
Su-Jien Lin

Static-gap, single-spark tests were used to investigate the arc erosion behavior of newly developed silicon carbide and alumina particle reinforced silver matrix composites (SiCp/Ag, Al2O3p/Ag). Craters and hills exist on the surfaces of eroded silver matrix composites, and their depths and sizes decrease as the particle content increases and the particle size decreases. Obvious melting, flow, severe splash of molten silver, and the segregation of particles are present on the surfaces of eroded composites containing low volume percents of large particles. Easier silver flow results in smooth surfaces and reduces the total surface areas of the eroded composites containing large particles. The flow and splash of silver decreased with increasing particle content and decreasing particle size, exhibiting a better erosion resistance to single-spark tests. The static-gap, single-spark erosion behavior of silver matrix composites is dominated by the flow and splash of molten composites. A high viscosity of the liquids provides the composites a good arc erosion resistance.


Author(s):  
N. Kedir ◽  
C. Gong ◽  
L. Sanchez ◽  
M. J. Presby ◽  
S. Kane ◽  
...  

Erosion behavior of a large number of gas-turbine grade ceramic matrix composites (CMCs) was assessed using fine to medium grain garnet erodents at velocities of 200 and 300 m/s at ambient temperature. The CMCs used in the current work were comprised of nine different SiC/SiCs, one SiC/C, one C/SiC, one SiC/MAS, and one oxide/oxide. Erosion damage was quantified with respect to erosion rate and the damage morphology was assessed via SEM and optical microscopy in conjunction with 3-D image mapping. The CMCs response to erosion appeared to be very complicated due to their architectural complexity, multiple material constituents, and presence of pores. Effects of architecture, material constituents, density, matrix hardness, and elastic modulus of the CMCs were taken into account and correlated to overall erosion behavior. The erosion of monolithic ceramics such as silicon carbide and silicon nitrides was also examined to gain a better understanding of the governing damage mechanisms for the CMC material systems used in this work.


Author(s):  
M. J. Presby ◽  
C. Gong ◽  
S. Kane ◽  
N. Kedir ◽  
A. Stanley ◽  
...  

Abstract Erosion phenomenon of ceramic matrix composites (CMCs), attributed to their unique architectural configurations, is markedly different from conventional monolithic ceramic counterparts. Prior to further integration of CMCs into hot-section components of aeroengines subject to erosive environments, their erosion behavior needs to be characterized, analyzed, and formulated. The erosion behavior of a 2-D woven melt-infiltrated (MI) SiC/SiC CMC was assessed in this work as a function of variables such as particle velocity and size. The erosion damage was characterized using appropriate analytical tools such as optical and scanning electron microscopy (SEM). A phenomenological erosion model was developed for SiC/SiC CMC material systems with respect to kinetic energy of impacting particles in conjunction with nominal density, matrix hardness and elastic modulus of the SiC/SiC CMCs. The model was in reasonable agreement with the experimental data.


2004 ◽  
Vol 39 (13) ◽  
pp. 4179-4184 ◽  
Author(s):  
Chia-Jung Hsu ◽  
Shou-Yi Chang ◽  
Liang-Yu Chou ◽  
Su-Jien Lin

Author(s):  
N. Kedir ◽  
C. Gong ◽  
L. Sanchez ◽  
M. J. Presby ◽  
S. Kane ◽  
...  

Erosion behavior of a large number of gas-turbine grade ceramic matrix composites (CMCs) was assessed using fine to medium grain garnet erodents at velocities of 200 and 300 m/s at ambient temperature. The CMCs used in the current work were comprised of nine different SiC/SiCs, one SiC/C, one C/SiC, one SiC/MAS, and one oxide/oxide. Erosion damage was quantified with respect to erosion rate and the damage morphology was assessed via scanning electron microscopy (SEM) and optical microscopy in conjunction with three-dimensional (3D) image mapping. The CMCs response to erosion appeared to be very complicated due to their architectural complexity, multiple material constituents, and presence of pores. Effects of architecture, material constituents, density, matrix hardness, and elastic modulus of the CMCs were taken into account and correlated to overall erosion behavior. The erosion of monolithic ceramics such as silicon carbide and silicon nitrides was also examined to gain a better understanding of the governing damage mechanisms for the CMC material systems used in this work.


Sign in / Sign up

Export Citation Format

Share Document