1. Novel metal materials, such as amorphous alloys and shape memory alloys with unique physical properties, have become a hot topic in their application to automobiles.
2. The present state of research into the toughening of new metal materials refers to the recent or ongoing development of metals of superior performance and higher quality.
In the process of developing these materials, in addition to traditional techniques, new technologies have been adopted, including micro-alloying, modification agent addition, continuous casting and rolling, rapid solidification, amorphous structure, controlled rolling, controlled forging, deformation heat treatment, surface strengthening, superplasticity, and material composites.
I. Magnesium and Magnesium Alloys
Due to their superior physical properties and machinability, coupled with their abundant reserves, magnesium and its alloys are recognized within the industry as the most promising lightweight materials and green metal materials of the 21st century.
In the coming decades, magnesium will be the fastest growing non-ferrous metal in demand.
1. Magnesium Alloys in Transport Products such as Cars and Motorcycles.
Since the 1970s, stricter restrictions on energy conservation and exhaust emissions of cars have been imposed, especially in developed countries.
European car manufacturers proposed a new concept of the “3-liter gasoline car” in 1993-1994, while the United States introduced the “PNGV” (Next Generation Vehicle) cooperation program.
The aim was to produce affordable cars that consume only 3 liters of fuel per 100 kilometers, with at least 80% of the components recyclable. These requirements forced car manufacturers to adopt high-tech methods to produce lighter, fuel-efficient, and environmentally friendly vehicles.
It’s estimated that a 10% reduction in car weight can improve fuel efficiency by 5.5%. If each car could use 70 kilograms of magnesium, the annual CO emissions could be reduced by over 30%.
As the lightest structural metal material in practical applications, magnesium’s role in reducing car weight and improving performance is gaining attention. Major car companies around the world have made magnesium alloy parts a significant development focus.
In Western countries, car manufacturers are vying to use magnesium alloy parts as a symbol of their vehicle’s superiority. Volkswagen, Audi, and Fiat are all using magnesium alloys.
In the early 1990s, the weight of magnesium alloys used in European and American cars averaged about 1 kilogram per car. By 2000, this had increased to around 3.6 kilograms.
Currently, major car manufacturers in Europe and America are planning to increase the use of magnesium alloys in each car to 100-120 kilograms over the next 15-20 years.
Experts predict that in the next 7-8 years, magnesium usage in European cars will account for 14% of total consumption, expected to increase at a rate of 15% and reach 200,000 tons by 2005.
2. Magnesium Alloys in Electronics and Household Appliances
The high demand for magnesium alloys in the automotive industry has led to several breakthroughs in magnesium alloy production technology, significantly reducing the cost of using magnesium alloys.
This cost reduction has promoted the development of magnesium alloys in industries such as computers, telecommunications, instrumentation, appliances, medical, and light industry.
Among these, the fastest growing applications of magnesium alloys are in the electronics and instrumentation industries.
Under the requirements for thin walls, miniaturization, and impact resistance, along with considerations for electromagnetic shielding, heat dissipation, and environmental protection, magnesium alloys have become the best choice for manufacturers.
Additionally, magnesium alloy casings make products more luxurious and visually appealing. Although the weight and size of magnesium alloy products in the electronics and instrumentation industries are smaller than automotive parts, their large quantity and wide coverage mean that their usage is considerable.
Thus, in recent years, the consumption of magnesium alloys in the electronics industry has surged, becoming another significant factor in the increase in global magnesium consumption.
3. Other Applications
Other uses include as an additive in aluminum alloys, magnesium sacrificial anodes, and magnesium alloys for profiles, among others. Magnesium sacrificial anodes, an effective method for preventing metal corrosion, are widely used in long-distance underground iron pipelines and oil tanks.
Currently, magnesium alloys used as sacrificial anodes have a market demand of 30,000 to 40,000 tons per year, growing at a rate of 20% annually.
Magnesium alloy profiles and pipes, formerly mainly used in cutting-edge or defense sectors such as aerospace, have seen increased application in civilian areas due to improvements in magnesium alloy production capacity and technology.
Their production costs have dropped to levels comparable to aluminum alloys, significantly stimulating their use in applications such as bicycle frames, wheelchairs, rehabilitation and medical equipment, and fitness equipment.
II. Titanium and Titanium Alloys
Titanium and titanium alloys possess excellent characteristics such as low density, high specific strength, and good corrosion resistance.
With the development of the national economy and defense industry, titanium is increasingly recognized and widely used in fields such as automobiles, electronics, chemical industry, aviation, aerospace, and weaponry.
Looking at the production and proportion of major titanium-producing countries since 2002, the United States, the Commonwealth of Independent States, and Japan hold important positions.
The United States accounts for 28.3%, the Commonwealth for 29.7%, and Japan for 25.3%, with a combined production accounting for 83% of the world’s total.
In terms of titanium application fields, using the United States and Japan as examples, the largest application field of titanium in the United States is aerospace, accounting for 58.5% of the total consumption; in Japan, it is thermal power, nuclear power plants, and plate heat exchangers, which together account for 41.9% of the total consumption.
As can be seen from the table below, compared to the United States, Japan uses titanium in a wider range of applications.
In sports goods, besides using titanium in golf club heads, there are also spikes for short-distance running shoes, badminton rackets and ice axes for mountaineering equipment, ice skate blades for skiing and skating, bicycle frames, wheelchairs, and so on.
Both the United States and Japan are increasing their use of titanium in the chemical industry and oil and gas drilling equipment.
Titanium is cleverly used in computer disks (vacuum coating), frames of fiber spinning machines, cutlery, tent equipment, crutches, and cameras, among other things.
III. Aluminum and Aluminum Alloys
Aluminum alloys, characterized by their low density, good thermal conductivity, ease of forming, and low cost, are extensively used in aerospace, transportation, and light industry construction sectors, making them the most widely used and highest volume alloys in the light metal category.
With the development of the power industry and breakthroughs in smelting technology, their cost-effectiveness has significantly improved. Currently, the transportation industry has emerged as the largest user of aluminum alloy materials.
Globally, the transportation industry has become the primary consumer of aluminum, accounting for 27.6% of the world’s total aluminum output in 2001, even exceeding 30% in some countries.
As the modernization process of the transportation industry accelerates, the application of aluminum and its alloys in the three major areas of aerospace and automotive industries continues to grow.
1. Application of Aluminum Alloys in Aerospace
Aluminum alloys are the primary materials used in subsonic aircraft, accounting for 70% to 80% of the structure of current commercial aircraft. For instance, each plane incorporates 400,000 to 1.5 million aluminum alloy rivets.
According to statistics from Boeing, the production of 316,000 various commercial aircraft has consumed 7.1 million tons of aluminum, averaging 22 tons per aircraft.
Although the proportion of aluminum components in advanced military aircraft is somewhat lower, it still constitutes 40% to 60% of the total mass. Predictions for 2010 placed global aerospace aluminum consumption at 600,000 tons, with an average annual growth rate of about 4.5%.
The price of aerospace aluminum is much higher than that of ordinary civilian aluminum, being approximately 18 times that of the latter, making it a highly important market with significant political and military implications.
In 2002, the price of US aerospace aluminum was between $33,000 and $44,100 per ton, while ordinary civilian aluminum was only priced between $2,200 and $3,500 per ton.
As a world juggernaut in the aerospace industry, the US consumes over 50% of the global aluminum used in this field, with other countries such as France, Russia, China, Japan, Brazil, Canada, and the UK accounting for less than 50%.
In 2002, the global consumption of aluminum for aerospace was approximately 420,000 tons, with the US contributing 214,000 tons. Alcoa, an American industrial corporation, is a leading supplier of aerospace aluminum, providing more than 35% of the global supply.
To maintain its dominant position in this field and secure higher profits, Alcoa proposed a comprehensive research and planning initiative in 2002 called the “20-20 Initiative”.
The plan’s goals included developing a range of new high-performance aluminum alloys over the next 20 years, improving the design of aluminum components, adopting advanced manufacturing technologies, reducing the weight of aluminum components by 20%, and cutting the manufacturing and maintenance costs of these components by 20%.
Al-Li alloys, with their low density, high specific strength, high specific stiffness, excellent low-temperature performance, good corrosion resistance, and outstanding superplastic forming properties, are considered ideal structural materials in the aerospace industry.
Replacing conventional aluminum alloys with Al-Li alloys can decrease the weight of components by 15% and increase stiffness by 15% to 20%.
In the field of spaceflight, Al-Li alloys have already replaced conventional high-strength aluminum alloys in many components. Al-Li alloys offer significant advantages as structural materials for storage boxes and instrument compartments.
It’s forecasted that Al-Mg alloys containing Scandium and other series of aluminum alloys may become important structural materials for the next generation of aircraft.
In addition to directly serving as structural materials, TiAl-based alloy sheets can also be used as preformed materials for superplastic forming, and for manufacturing near-net-shaped aircraft and spacecraft engine components, as well as wings and shells for hypersonic vehicles.
2. Application of Aluminum Alloys in Automobiles
Aluminum and its alloys are the earliest lightweight metal materials used in automobile manufacture, proving to be the most economical, practical, and competitive lightweight engineering materials for vehicles.
They offer numerous advantages in terms of production cost, part quality, and material utilization rate.
Three-quarters of the aluminum alloy materials used in automobiles are cast aluminum alloys, primarily found in engine components, transmission parts, and chassis moving parts. Deformed aluminum alloys are mainly used for heat exchanger systems and body components.
It is projected that within the next decade, 95% of cylinder heads and 50% of passenger car engine cylinders will be made of aluminum alloys, with goals for light trucks set at 60% and 25% respectively.
Aluminum-based composites are replacing traditional automotive materials like aluminum alloys, steel, and ceramics in certain ranges, especially for key automobile parts, particularly those in high-speed motion.
These composites play a very positive role in reducing mass, lowering inertia, reducing fuel consumption, improving emissions, and enhancing overall vehicle performance, showing promising application prospects in the automotive industry.
Aluminum foams are considered to be a promising material for future automobile production. Their application in car manufacturing involves sandwich-like triplates, which consist of a core layer of aluminum foam or aluminum alloy foam, flanked by aluminum plates or other metal sheets.
The German Karmann automobile company has manufactured the Ghiaroadster’s top cover plate using a sandwich composite of foam aluminum, which is about seven times stiffer than the original steel component and 25% lighter.
It is estimated that about 20% of automobile body components could be made from foam aluminum. If a midsize sedan were to adopt foam aluminum for certain parts, it could reduce the weight by approximately 27.2 kg, saving energy and reducing environmental pollution.
Utilizing foam aluminum structures could greatly simplify the structural system, reducing the number of parts by at least one-third.
According to statistics from the International Aluminum Institute (IAI), the application of aluminum and its alloys in automobiles doubled from 1991 to 1999 and is expected to double again by 2005.
It is projected that by 2005, American automobiles will use over 130 kg of aluminum and its alloys per vehicle, while the figure for Western Europe will reach 119 kg per vehicle.
