Titanium Alloys

The following sections are included:

• Preface
• Contents

The following sections are included:

• History of titanium and its alloys
• Commercial breakthrough
• Basic properties of titanium
• Primary Ti metal production
  • The Kroll process
• Classification of titanium alloys
• Mechanical properties of titanium alloys
  • Effect of interstitial elements on mechanical properties
• Titanium industry: Current and future status
• References

The following sections are included:

• Crystal structure of Ti alloys
• Classification of titanium alloy
• Various phases of Ti alloys
  • Equilibrium phase — α phase
  • Non-equilibrium phases β ′, α ′, α ″, and ω
  • Phase transformation of β → α ′, α ″
  • Phase transformation of β → ω
  • Phase transformation of β → β + β ′
  • Other non-equilibrium phases
• Factors influencing phase transformation and microstructure of Ti alloys
  • The influence of different factors on phase transformation of Ti alloys
  • The influence of different factors on microstructures of Ti alloys
• References

The occurrence of an allotropic transformation in pure titanium (Ti) regulates the formation of structures achievable through the heat treatment of Ti alloys. Consequently, thermal treatment can adjust the mechanical properties of such alloys. This chapter briefly introduces heat treatment of Ti and Ti alloys. Detailed information is available in the ASM Handbook 4E [1].

The following sections are included:

• Introduction
• Fully/single-phase α alloys
  • Processing and microstructure
• Near-α alloys
  • Processing and microstructure
• Ti–Cu alloy
• References

The following sections are included:

• Introduction
• Design approaches of biomedical β-type titanium alloys
  • Molybdenum equivalency (Mo_eq) method
  • The DV-Xα molecular orbital design method
• Various techniques for preparing porous β-type Ti alloys
  • Powder metallurgy
  • Additive manufacturing
  • FAST-forge
• Conclusion and future outlook
• References

The following sections are included:

• Introduction
• Thermomechanical processing and common microstructures of α + β alloys
  • Fully lamellar microstructure
  • Bi-modal microstructures
  • Fully equiaxed microstructure
• Correlation between microstructure and mechanical properties
  • Fully lamellar microstructures
  • Bi-modal microstructures
  • Fully equiaxed microstructures
  • Ti–6Al–4V
• References

The following sections are included:

• Introduction
• TiNi shape memory alloys
  • Features
  • Applications
• Ti-Al aluminides
  • Features
  • Applications
• High-creep-resistant Ti alloys
  • Features
  • Applications
• Anti-inflammatory Ti alloys
  • Features
  • Applications
• Future directions
• References

Titanium matrix composites (TMCs) offer remarkable specific strength and stiffness compared to steel- and nickel-based materials. High-temperature TMCs, whether reinforced with continuous fibers or discontinuous particulates, can achieve up to a 50% reduction in weight relative to monolithic superalloys, all while maintaining comparable strength and stiffness. This makes them particularly valuable in jet engine propulsion systems. The exceptional properties of TMCs have propelled them to the forefront of extensive global research and development programs. Despite being one of the most studied and sought-after material systems, information about the properties, fabrication methods, and design of TMCs is often scattered in the literature. This chapter aims to consolidate essential research findings that have contributed to advances in TMCs. It provides comprehensive details about common reinforcements, manufacturing processes, and the mechanical properties of some widely used TMCs. Additionally, this chapter highlights typical industrial applications of TMCs and emphasizes the promising outlook for these advanced materials.

The most crucial feature of titanium, also a lingering challenge for many manufacturing processes, is its high affinity to interstitial elements such as oxygen, carbon, etc. The great affinity to interstitial elements is combined with a strong influence on the mechanical properties, even at low contents in the 0.1–0.4 wt.% range. Increasing the impurity level increases the tensile strength but decreases ductility. Among the interstitial elements, oxygen is the most crucial element due to its influence on mechanical properties, particularly elongation (EL). Significant research and development activities involving Ti materials have been devoted to solving this ductility/strength dilemma in recent years. This chapter briefly reviews the recent advances in this area.

The following sections are included:

• Introduction
• Additive manufacturing
• Powder bed fusion
  • Laser-powder bed fusion
  • Electron beam melting
• Direct energy deposition
• Mechanical properties of additively manufactured Ti alloys
  • α–Ti alloys
  • (α + β) –Ti alloys
  • β –Ti alloys
• Conclusions
• References

The following sections are included:

• Introduction
• Historical development
• Case studies of Ti and its alloys in the aerospace field
  • Applications of Ti and its alloys in the aerospace field
• Case studies of Ti and its alloys in the biomedical field
  • Applications of Ti and its alloys in the biomedical field
• Case studies of Ti and its alloys in the marine field
  • Application of Ti and its alloys in the marine field
• Case studies of Ti and its alloys in the automobile field
  • Application of Ti and its alloys in the automobile field
• Challenges
• Conclusion
• References

The following section is included:

• Index