Selecting the correct material is among the most crucial choices a mechanical engineer can make. Machine performance, life span, weight, price, and manufacturing process are all heavily influenced by the material selected.
The Need for Material Selection
A mechanical part needs to be able to handle the operating environment. Parts subjected to heavy forces may require high strength, whereas parts subjected to chemicals may need high resistance to corrosion.
For these reasons, an engineer takes into account many properties when choosing a material:
Strength and stiffness
Hardness and resistance to abrasion
Mass and density
Resistance to corrosion
Heat resistance
Production requirements
Cost and availability
Strongest is not necessarily best. In most cases, an engineer must choose the material that best meets the balance between performance, manufacturing, and cost.
Metals for Machine Building
Despite newer developments, metals are still commonly used in mechanical engineering, largely due to their strength, toughness, and manufacturability.
Steel
Steel is one of the most popular materials in engineering. Various steel grades can offer high strength, toughness, hardness, or resistance to wear and corrosion. Steel is often used to produce shafts, gears, frames, tools, and many other components of machines.
Aluminum
Aluminum is used mainly for its relatively low weight and good resistance to corrosion. Aluminum is frequently used when a reduction in the mass of a structure or a part is required.
Titanium
Titanium has a very favorable ratio between low density and high strength. Although titanium tends to be more expensive and more difficult to work with than other metals, it can be very useful in applications where weight and performance are critical.
New Materials for Mechanical Engineering
In addition to traditional metal materials, polymers, ceramics, and composite materials are being used in modern mechanical engineering. These materials can offer properties not found in traditional materials.
For example, a composite material may combine two or more materials to achieve a specific balance of strength, stiffness, and low weight.
Such material combinations can be especially useful in applications where performance and weight are of great importance.
Material and Production Considerations
Material selection should never be considered without taking into account production. A material may exhibit excellent mechanical properties but still be impractical to use if it is too difficult or expensive to process.
An engineer must determine whether a component will be machined, cast, forged, welded, molded, or manufactured using additive manufacturing. Each of these processes affects the final properties, size, surface quality, and cost of a component.
This is why a mechanical engineer should think about the production process of a component even before they start designing it.
Materials and Environmental Impact
Another factor to consider when choosing a material is the environmental impact. An engineer should not only consider how well a material performs, but also how it impacts the environment over its entire life cycle.
Recyclability, material usage, component lifetime, maintenance, and energy consumption during production are becoming increasingly important factors in modern product development.
A part designed to last longer with efficient material usage can help reduce waste and increase the lifetime of a machine.
What’s Next for Engineering Materials?
Advancements in material science continue to expand the options available to mechanical engineers. New alloys, composite materials, engineered polymers, and materials designed specifically for additive manufacturing are constantly emerging.
To become a successful mechanical engineer, understanding materials will always be important. While advanced software programs can assist in analyzing and comparing materials, a final engineering decision ultimately comes down to knowing how a material will perform under real-world conditions.
At MachinePeak, we believe that good mechanical engineering begins with understanding the relationship between materials, design, production, and performance.
