The strength and weight of the metal are two of the most important factors to consider when selecting a material for a metal part. Many applications necessitate both high strength and low weight, but finding a material that can meet both requirements can be difficult.
Titanium and aluminum are two of the most common metals, both of which have high strength-to-weight ratios. When steel or other common materials are too heavy for the application, these metals are frequently used—for example, in the aerospace industry, where every pound of weight increases costs and must be minimized as much as possible.
While titanium and aluminum are both strong, lightweight nonferrous metals, their properties, and applications are very different. This article will compare and contrast titanium and aluminum in terms of physical and mechanical properties, as well as use cases, to assist you in deciding which metal is best for your application.
Titanium vs. Aluminum Properties
To begin with, consider the characteristics that titanium and aluminum share. Both metals have excellent heat tolerance and corrosion resistance in addition to their excellent strength-to-weight ratios. Neither is magnetic because they are nonferrous metals.
The similarities, however, end there. Though aluminum has a high strength-to-weight ratio, it is not nearly as strong as titanium. Aluminum has tensile strengths ranging from 35 to 80 ksi depending on the type of alloy used. Commercially pure titanium has a tensile strength comparable to aluminum alloy, but titanium alloys such as 6-4 titanium have tensile strengths of up to 160 ksi.
While both titanium and aluminum are lightweight, aluminum’s density of about 0.1 lb/in3 is much lower than titanium’s density of 0.16 lb/in3. This means that a titanium part will be heavier than an aluminum part of the same size, but titanium requires less material to achieve the same strength.
There are also differences in electrical and thermal conductivity between titanium and aluminum. Titanium is a poor conductor, with approximately 3.1% of the conductivity of copper. Aluminum, on the other hand, has approximately 64% of the conductivity of copper.
Finally, there is a significant cost difference between titanium and aluminum. Aluminum is extremely inexpensive and abundant, making it a cost-effective metal for a wide range of applications. Titanium is regarded as a relatively costly material. While titanium increases cost, it can also increase value because titanium parts are lighter, stronger, and more durable than aluminum ones.
Titanium vs. Aluminum Applications
Aluminum is the most abundant metal on the planet, so it stands to reason that it has a wide range of applications. Aluminum is used in almost every application that requires low weight and high strength, such as aircraft, building materials, bicycle frames, boats, and automotive frames. Some of the stronger alloys are used to make plastic molds. Due to its low cost, aluminum is commonly used in high conductivity applications such as electrical wiring, heat exchangers, and cookware due to its high conductivity and low cost.
Titanium is also used in aircraft and vehicles that require even greater strength. Due to its biocompatibility, titanium is frequently used in medical applications such as joint replacements, pacemakers, cranial plates, and dental implants.
Aluminum and titanium share properties that make them valuable materials in chemical, marine, automotive, and aerospace applications where strength, weight, and corrosion resistance are important considerations. In these cases, the decision between titanium and aluminum is frequently influenced by space and cost. When a high strength-to-weight ratio is required, titanium is the superior choice because it can handle high-strength requirements while taking up less space than aluminum. When the strength-to-weight ratio of aluminum is adequate for the application, it is a more cost-effective choice.
Another consideration when deciding between titanium and aluminum is machining waste. While machining inexpensive aluminum isn’t difficult, titanium is more valuable, and the material costs can quickly add up. As a result, aluminum is frequently used as a prototyping material for parts that will ultimately be made of titanium.