läsvärt ang. FRM
Har ju dykt upp lite frågor då och då om frm blocken som finns i B21/H23/H22/F20C/F22C/C30A/C32A
Sprang på denna länk, kanske ger lite mer kunskap.
(Saffil är företaget som honda anlitade för detta)
<a href="http://www.saffil.com/pdfs/automotive/data/mmcprop.pdf" target="_blank">http://www.saffil.com/pdfs/automotive/d ... rop.pdf</a>
PROPERTIES OF METAL MATRIX COMPOSITES
Saffil has been actively involved in the development
of metal matrix composite (MMC)applications since
1980,producing grades of Saffil fibre tailored to meet
the stringent echnical requirements of reinforced
aluminum components such as pistons and engine
blocks.
The driving force behind new engine work is the need
to build lightweight units capable of delivering higher
performance,improved fuel economy,lower
emissions and reduced noise levels.
For more than a decade,Kolben Schmidt,Mahle,AE
and Toyota have pioneered the use of Saffil fibre
reinforced pistons for diesel engines,while Honda
Motor Company focused on the reinforcement of
engine blocks.
In 1990,Honda launched a new generation of
aluminum engine blocks with fibre reinforced cylinder
walls replacing traditional cast iron liners.The first
model selected for production was the Prelude Si,a
16 valve in-line 4-cylinder engine,using a new
casting process to incorporate the Saffil -carbon fibre
hybrid preforms.
Elimination of he cast iron liner using MMC
technology allows a reduction in material thickness
between the adjacent bores.Tightening the cylinder
spacing in this way results in reduction in he overall
length of the engine and a weight saving on the block
of around 4.5kg.
Honda has since expanded the use of MMC engine
blocks and include models of he Accord,Ascot
Innova and the S2000.
Honda has also developed a high pressure die
casting (HPDC)process for manufacturing the MMC
engine blocks which reduces process costs and
enables widely available equipment to be employed
(See tables 8 and 9)
KS Aluminum-Technologie AG is also using Saffil
fibres with silicon particles (LOKASIL)in engine
blocks and at 17%loading o reinforce the cylinder
head in a turbo charged,4-valve diesel engine.The
cylinder head is produced by squeeze casting.
Figs.1 to 6 and tables 2 to 4 show data for
composites based on typical piston alloys.In all
cases,the Saffil fibre was incorporated in an
approximately random planar orientation.
At 300 o C,the presence of the fibre has improved the
ultimate tensile strength (fig.1)by a factor of 4.I
also extends the maximum use limit of the alloy to
around 500 o C,a peak temperature which is
sometimes approached in he combustion bowl rim of
diesel engine pistons.
Useful improvements in high temperature fatigue
strength are demonstrated by the data in table 2 and
fig.2.The scatter displayed by the pure alloy is
almost eliminated by adding the fibre.The modulus
has been increased to values in excess of those
predicted by theory for a random planar array of
fibres.This indicates strong fibre -matrix bonding and
also the effect of modified matrix microstructure.At
300 o C,the composites containing 18%and 24%fibre
have a higher modulus than the unreinforced alloy at
25 o C (fig.3).
The coefficients of thermal expansion are lower than
in the pure alloy (table 2)and the difference
increases with the volume fraction of fibre.
The thermal conductivity is lower than for the
unreinforced metal and decreases as the fibre level
rises (fig.4).It is higher in the direction parallel to
fibre orientation planes than in the normal direction,
but in all cases,is much higher than for Niresist iron
which is frequently used for piston inserts.
The wear resistance of the alloy is greatly improved
by including only a small volume fraction of fibre.Fig
5 shows data for 4.4%v/v addition of RG grade Saffil
fibre.Wear of the mating component,in this case Cr-
steel,might be increased by contact with the
reinforced alloy,but can be avoided by using RG
grade fibre with the appropriate alpha alumina level.
Additional wear data giving results for a higher fibre
loading and also a comparison with Niresist are
shown in Fig.6.
The hardness at 25 o C increases linearly with
increasing volume fraction of fibre to a value over
60%greater han the unreinforced alloy for a volume
fraction of 0.24 (table 4).As expected the composites
also display much greater hardness than the pure
alloy at elevated temperatures (table 2).
Other Alloys
All he preceding composites data refer to alloys
commonly used in pistons.Composites based on
other alloys show enhanced ultimate tensile strength
even at room temperature.For example,(fig 7).Such
composites usually show higher strain o failure than
those based on piston alloys (table 5).The presence
of he fibre in aluminum alloys generally results in
modified microstructure.(fig and in particular,in a
reduced grain size.
Sprang på denna länk, kanske ger lite mer kunskap.
(Saffil är företaget som honda anlitade för detta)
<a href="http://www.saffil.com/pdfs/automotive/data/mmcprop.pdf" target="_blank">http://www.saffil.com/pdfs/automotive/d ... rop.pdf</a>
PROPERTIES OF METAL MATRIX COMPOSITES
Saffil has been actively involved in the development
of metal matrix composite (MMC)applications since
1980,producing grades of Saffil fibre tailored to meet
the stringent echnical requirements of reinforced
aluminum components such as pistons and engine
blocks.
The driving force behind new engine work is the need
to build lightweight units capable of delivering higher
performance,improved fuel economy,lower
emissions and reduced noise levels.
For more than a decade,Kolben Schmidt,Mahle,AE
and Toyota have pioneered the use of Saffil fibre
reinforced pistons for diesel engines,while Honda
Motor Company focused on the reinforcement of
engine blocks.
In 1990,Honda launched a new generation of
aluminum engine blocks with fibre reinforced cylinder
walls replacing traditional cast iron liners.The first
model selected for production was the Prelude Si,a
16 valve in-line 4-cylinder engine,using a new
casting process to incorporate the Saffil -carbon fibre
hybrid preforms.
Elimination of he cast iron liner using MMC
technology allows a reduction in material thickness
between the adjacent bores.Tightening the cylinder
spacing in this way results in reduction in he overall
length of the engine and a weight saving on the block
of around 4.5kg.
Honda has since expanded the use of MMC engine
blocks and include models of he Accord,Ascot
Innova and the S2000.
Honda has also developed a high pressure die
casting (HPDC)process for manufacturing the MMC
engine blocks which reduces process costs and
enables widely available equipment to be employed
(See tables 8 and 9)
KS Aluminum-Technologie AG is also using Saffil
fibres with silicon particles (LOKASIL)in engine
blocks and at 17%loading o reinforce the cylinder
head in a turbo charged,4-valve diesel engine.The
cylinder head is produced by squeeze casting.
Figs.1 to 6 and tables 2 to 4 show data for
composites based on typical piston alloys.In all
cases,the Saffil fibre was incorporated in an
approximately random planar orientation.
At 300 o C,the presence of the fibre has improved the
ultimate tensile strength (fig.1)by a factor of 4.I
also extends the maximum use limit of the alloy to
around 500 o C,a peak temperature which is
sometimes approached in he combustion bowl rim of
diesel engine pistons.
Useful improvements in high temperature fatigue
strength are demonstrated by the data in table 2 and
fig.2.The scatter displayed by the pure alloy is
almost eliminated by adding the fibre.The modulus
has been increased to values in excess of those
predicted by theory for a random planar array of
fibres.This indicates strong fibre -matrix bonding and
also the effect of modified matrix microstructure.At
300 o C,the composites containing 18%and 24%fibre
have a higher modulus than the unreinforced alloy at
25 o C (fig.3).
The coefficients of thermal expansion are lower than
in the pure alloy (table 2)and the difference
increases with the volume fraction of fibre.
The thermal conductivity is lower than for the
unreinforced metal and decreases as the fibre level
rises (fig.4).It is higher in the direction parallel to
fibre orientation planes than in the normal direction,
but in all cases,is much higher than for Niresist iron
which is frequently used for piston inserts.
The wear resistance of the alloy is greatly improved
by including only a small volume fraction of fibre.Fig
5 shows data for 4.4%v/v addition of RG grade Saffil
fibre.Wear of the mating component,in this case Cr-
steel,might be increased by contact with the
reinforced alloy,but can be avoided by using RG
grade fibre with the appropriate alpha alumina level.
Additional wear data giving results for a higher fibre
loading and also a comparison with Niresist are
shown in Fig.6.
The hardness at 25 o C increases linearly with
increasing volume fraction of fibre to a value over
60%greater han the unreinforced alloy for a volume
fraction of 0.24 (table 4).As expected the composites
also display much greater hardness than the pure
alloy at elevated temperatures (table 2).
Other Alloys
All he preceding composites data refer to alloys
commonly used in pistons.Composites based on
other alloys show enhanced ultimate tensile strength
even at room temperature.For example,(fig 7).Such
composites usually show higher strain o failure than
those based on piston alloys (table 5).The presence
of he fibre in aluminum alloys generally results in
modified microstructure.(fig and in particular,in a
reduced grain size.
Prelude Si 2.0 -89
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