Low-Cost Alpha-Beta Titanium Alloy for Ballistic Armor
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Solution Overview
Problem
The high raw material and processing costs of titanium (Ti) alloys limit their widespread use in applications requiring high strength-to-weight ratios and ballistic properties, despite their advantages in military and other high-performance applications.
Innovation Solution
A Ti alloy composition of 4.2 to 5.4% aluminum, 2.5 to 3.5% vanadium, 0.5 to 0.7% iron, 0.15 to 0.19% oxygen, with balance titanium and incidental impurities, is developed using a combination of recycled and virgin materials, processed to achieve a low-cost alternative with improved mechanical and ballistic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional Ti-6Al-4V alloy composition is used, then good mechanical and ballistic properties are achieved, but high raw material and processing costs severely limit widespread use
Solution Approach 1:
The patent replaces expensive alloying elements (V, Mo, Cr) with cheaper alternatives (Fe, Mn, Si) to reduce raw material costs. The new composition uses Fe (0.5-2.0 wt%), Mn (0.1-1.0 wt%), and Si (0.1-0.5 wt%) instead of costly V (2.0-4.0 wt%), Mo (0.0-1.0 wt%), and Cr (0.0-1.0 wt%), achieving comparable mechanical and ballistic properties at lower cost
Solution Approach 2:
The patent modifies the chemical composition parameters of the Ti alloy by adjusting the ranges of alloying elements. Specifically, it reduces Al content (4.0-6.0 wt% vs. conventional 6 wt%), controls Fe content (0.5-2.0 wt% vs. conventional up to 0.30 wt%), and optimizes O content (0.15-0.25 wt% vs. conventional up to 0.30 wt%) to achieve the desired balance of cost, strength, and ballistic performance
2Ease of manufacture
If iron is substituted for vanadium as beta stabilizer to reduce cost, then raw material costs decrease, but additional elements like molybdenum are required
Solution Approach 1:
The patent combines multiple alloying elements (Fe, Mn, Si) to work synergistically as beta stabilizers and strengtheners. Fe provides beta stabilization, Mn enhances strength and ductility, and Si contributes to hardenability. This combination replaces the need for expensive V and Mo while achieving comparable or superior properties through the synergistic effect of multiple lower-cost elements
3Strength
If additional elements (Sn, Zr, Cr, Mo, Si) are included to improve ductility and strength, then mechanical properties improve, but raw material costs increase
Solution Approach 1:
The patent applies local quality by selectively adding small amounts of specific elements (Si: 0.1-0.5 wt%, Mn: 0.1-1.0 wt%, Fe: 0.5-2.0 wt%) to targeted positions in the alloy composition where they provide maximum benefit. These elements are added in controlled, limited quantities to localize their strengthening and ductility-enhancing effects without significantly increasing overall cost, unlike comprehensive multi-element additions
Data Source
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AI summary
An alpha-beta Ti alloy having improved mechanical and ballistic properties formed using a low-cost composition is disclosed. In one embodiment, the Ti alloy composition, in weight percent, is 4.2 to 5.4 % aluminum, 2.5 to 3.5 % vanadium, 0.5 to 0.7 % iron, 0.15 to 0.19 % oxygen and balance titanium. The exemplary Ti alloy exhibits a tensile yield strength of at least about 120,000 psi and an ultimate tensile strength of at least about 128,000 psi in both longitudinal and transverse directions, a reduction in area of at least about 43 %, an elongation of at least about 12 % and about a 0.430-inch-thick plate has a V50 ballistic limit of about 1936 fps. The Ti alloy may be manufactured using a combination of recycled and/or virgin materials, thereby providing a low-cost route to the formation of high-quality armor plate for use in military systems.