Requirements of the materials in automotive (from Materials in automobile applications)
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Light weight
o To improve fuel efficiency in the transportation
o The single main obstacle in application of lightweight materials is their high cost, priority
is given to activities to reduce costs through development of new materials, forming
technologies and manufacturing processes.
o To achieve lightweight construction, without compensating on rigidity, automakers have
been investigating the replacement of steel with aluminum, magnesium, composites
and foams.
o Material properties of steel together with ease of manufacture and low cost mean that
steel intensive vehicles have by far the largest share of the market.
 The high cost of alternative materials such as aluminum or composites mean
that steel’s position as the first choice material could be still secure
Cost
o Actual cost of raw materials
o Manufacturing value added
o Cost to design and test the product
o The ability to approach the total cost of the competition, therefore, must be associated
with lower component manufacturing costs
o Compared to cast irons and steel, cast aluminum and magnesium components are
potentially less costly
 This is based on their reduced manufacturing cycle times, better machinability,
ability to have thinner and more variable wall dimensions, closer dimensional
tolerances, reduced number of assemblies, more easily produce to near net
shapes (decreases finishing costs, and less costly melting/metal forming
processes)
 However, because wrought aluminum and magnesium components are almost
always more costly to produce than their ferrous counterparts.
Use stage is the most significant contributor in terms of energy consumption, and air and water
emissions. This justifies the effort of the automotive manufacturers to use lighter-weight
material and new powertrain technologies in its vehicles.
Aluminum is better in terms of fuel economy than steel. A 10 % reduction in mass produces a
5% improvement in fuel economy. It is suggested that replacing steel with aluminum or a
composite material not only increases the fuel economy but also reduces the overall life cycle
emissions and energy consumption.
Crashworthiness
Recyclable
a. Review of Al in automobiles -- impetus and comparison versus
steel
Currently, the use of aluminum in automobiles is facing two major challenges: the cost of the aluminum
is twice as high as steel and its manufacturing difficulties under mass production (Aluminum Alloys:
Promising Materials in the Automotive Industry, 2002). However, the efficiency of a structure should not
be evaluated simply in terms of the cost.
With the increasingly environmental concern on the automobile exhaust, many countries have
developed new policies to increase the fuel efficiency significantly. This cannot be done with the use of
steel, thus, aluminum should be an alternative.
Aluminum offers the ultimate automobile engineering solution that its density is three times lower than
steel, obtains a high corrosion resistance, qualifies for the torsion and stiffness requirement, and
possessing good formability (Automobile Bodies: Can Aluminum Be an Economical Alternative to Steel?,
2001). A reduction in mass can be attained by substituting aluminum alloys instead of steel. At 120 kg
per car for 10 million cars with a mean annual haulage of 15 thousand km can save 982 million liters of
fuel and reduce CO2 emission in the atmosphere by 2.3 million ton (Aluminum Alloys: Promising
Materials in the Automotive Industry, 2002). By increasing the fuel efficiency, the petroleum energy can
be saved. This can offset the additional energy needed to manufacture aluminum compared to steel
(Life-Cycle Energy Savings Potential from Aluminum Intensive Vehicles). Moreover, a high degree of
utilization of 85 to 95% of utilization can be achieved by recycling aluminum. Although the total energy
of production for virgin wrought aluminum is approximately 231 MJ/kg compared to the total energy of
production from virgin steel of 65 MJ/kg, the recycled production of aluminum and steel are both at 52
MJ/kg (Aluminum Alloys: Promising Materials in the Automotive Industry, 2002). In addition, the cost of
labor and maintenance can be reduced due to the high corrosion resistance obtained by the aluminum
alloy. The automobile body can preserve for 20 years even after its service life and it under severe
climate condition (Aluminum Alloys: Promising Materials in the Automotive Industry, 2002).