The combination of a high strength-to-weight ratio, excellent mechanical properties, and outstanding corrosion resistance makes titanium grades the ideal material choice for many critical applications.
Because the allotropic behavior of titanium allows diverse changes in microstructure through variations in thermomechanical processing, a broad range of properties and applications can be achieved with a minimum number of titanium grades. This is especially true for titanium alloys with a two-phase alpha plus beta (a+ß) crystal structure.
The most widely used titanium grade is the Ti-6Al-4V alpha-beta alloy. This titanium alloy is well understood and highly tolerant of variations in fabrication operations, even though its room-temperature shaping and forming characteristics are relatively poor compared with steel and aluminum. Because Ti-6Al-4V has limited section-size hardenability, it is most commonly used in the annealed condition.
Commercially pure titanium grades 1, 2, 3, and 4 are available in bar and billet. Several titanium alloys are also commonly available in bar and billet form, including Ti-6Al-4V (grades 5 and 24), Ti-5Al-2.5Sn (grade 6), Ti-0.2Pd (grades 7 and 11), Ti-3Al-8V-6Cr-4Zr-4Mo (also known as BETA-C), Ti-6Al-2Sn-4Zr-2Mo, Ti-8Al-1Mo-1V, Ti-6Al-6V-2Sn, Ti-10V-2Fe-3Al (TIMETAL 10.2.3), Ti-4Al-4Mo-2Sn (IMI 550), Ti-4Al-4Mo-4Sn-0.5Si-0.1C (IMI 551), Ti-15Mo (IMI 205), and TIMETAL 100.
Titanium alloys available in casting form include commercially pure titanium grades 2, 3, and 4, along with Ti-6Al-4V (grades 5 and 24), Ti-0.2Pd (grade 7), Ti-5Al-2.5Sn (grade 6), Ti-15V-3Cr-3Sn-3Al (TIMETAL 15.3), TIMETAL 1100, and Ti-5.8Al-4Sn-3.5Zr-0.7Nb (IMI 834).
By application, titanium alloys can be divided into three main groups: corrosion-resistant grades, high-strength grades, and high-temperature grades. By structure, there are three types of titanium alloys: alpha alloys, alpha-beta alloys, and beta or near-beta alloys.
Table 1. Titanium Alloy Classification
Classification
Typical Grades / Alloys
Key Characteristics
Typical Applications
Commercially Pure Titanium
Grades 1–4
Excellent corrosion resistance, good formability
Chemical processing, marine, medical
Alpha Alloys
Ti-5Al-2.5Sn
Good weldability, good high-temperature performance
Aerospace, cryogenic service
Alpha-Beta Alloys
Ti-6Al-4V, Ti-6Al-2Sn-4Zr-2Mo
Excellent balance of strength, toughness and corrosion resistance
Aerospace, biomedical, marine
Beta / Near-Beta Alloys
Ti-10V-2Fe-3Al, Ti-15Mo, BETA-C
Very high strength, good hardenability, excellent formability
Aerospace landing gear, high-strength components
This article classifies titanium by its commercially pure grades and alloy structures. The related guides in the Titanium series cover the topics you will need alongside it. Titanium Properties details the strength, low density, and corrosion resistance that distinguish one grade from another. Titanium Specifications explains the designation systems used to define each grade precisely, and Titanium Standards sets out the frameworks that govern those designations across different regions. Together, they connect grade classification with the properties, designations, and standards behind it.
Titanium grades fall into commercially pure titanium and titanium alloys. By application, they are grouped as corrosion-resistant, high-strength, and high-temperature grades, while by structure they are classified as alpha, alpha-beta, and beta or near-beta alloys.
Ti-6Al-4V, an alpha-beta alloy, is the most widely used titanium grade. It is well understood, tolerant of fabrication variations, and most commonly used in the annealed condition.
Commercially pure titanium is available as grades 1, 2, 3, and 4, which differ in their levels of strength and purity. These grades are commonly supplied in bar and billet form and are valued for their corrosion resistance.
Casting-form titanium alloys include commercially pure grades 2, 3, and 4, plus Ti-6Al-4V (grades 5 and 24), Ti-0.2Pd (grade 7), Ti-5Al-2.5Sn (grade 6), TIMETAL 15.3, TIMETAL 1100, and IMI 834.
Ti-6Al-4V has limited section-size hardenability, so it is most commonly supplied and used in the annealed condition to achieve a reliable balance of properties.