Review on Carbotanium Aditya Chandurkar

Outline Objective Titanium processing Carbon fibre Titanium Carbon fibre bonding Applications Future Work

Objective Smart material How it can be made Where can it be applied

Titanium Titanium is named after the Titans, the powerful sons of the earth in Greek mythology. Titanium is the forth abundant metal on earth crust (~ 0.86%) after aluminum, iron and magnesium. Have similar strength as steel but with a weight nearly half of steel. Not found in its free, pure metal form in nature but as oxides, i.e., ilmenite (FeTiO3) and rutile (TiO2)

Production of Titanium alloys Extraction process – Kroll process Melting Process ESR VAR EBM PAM Induction Skull Melting Casting process – Investment Casting, laser fabrication Forming Process – rolling, extrusion, forging Heat treatment

Physical Properties of TI Crystal Structure HCP (below 882.5 C) BCC (above 882.5 C) Atomic diameter 0.320 Density 4.54 g. cm-3 Melting Point 1667 Experiences allotropic transformation (α-> β) at 882.5 C Highly react with oxygen, nitrogen, carbon and hydrogen Difficult to extract -> expensive High strength and toughness Used mainly in wrought forms for advanced applications where cost is not critical

Classification of TI alloys Commercially pure (CP) titanium alpha and near alpha titanium alloys Alpha-beta titanium alloys Beta titanium alloys Different crystal structures and properties allow manipulation of heat treatments to produce different types of alloy microstructures to suit the required mechanical properties.

Beta Ti alloys Beta stabilizers are sufficiently added to retain a fully β structure (avoid martensite formation) when quenched from the β phase field Metastable β alloys : Mo Eq. <25 Stable β alloys : Mo Eq. 25-40

Beta titanium alloys β titanium alloys possess a BCC crystal structure, which is readily cold-worked (than HCP α structure) in the β phase field Microstructure after quenching contains equiaxed β phase After solution heat treating + quenching giving very high strength (up to 1300-1400 MPa) Metastable β Ti alloys are hardenable while stable β Ti alloys are non-hardenable

Composition and applications of β titanium alloys

Beta alloys Advantages Disadvantages High strength to density ratio Low modulus High strength/high toughness High fatigue strength Good deep hardenability Low forging temperature Strip producible Cold formable Easy to heat Excellent corrosion resistance Excellent combustion resistance Disadvantages High density Low modulus Poor low high temperature properties Small processing window High formulation cost High springback Microstructural instabilities Interstitial pick up

Carbon fibre Collection of thin stand of material mostly composed of carbon atoms. The carbon atoms are bonded together in microscopic crystals that are more or less aligned parallel to the long axis of the fiber. The crystal alignment makes the fiber incredibly strong for its size. Several thousand carbon fibers are twisted together to form a yarn, which may be used by itself or woven into a fabric The fabric is combined with epoxy is molded into shape to form various composite material

Classification of Carbon Fiber Carbon fibers are classified by the tensile modulus of the fiber. Tensile modulus is a measure of how much pulling force a certain diameter fiber can exert without breaking  Ultra-high-modulus (modulus >450Gpa) High modulus  (modulus between 350-450Gpa) Intermediate Modulus (modulus between 200-350Gpa) Low Modulus and high tensile (modulus < 100Gpa, tensile strength > 3.0Gpa) Super high tensile (tensile strength > 4.5Gpa)

Raw Materials 90% of the carbon fibers produced are made from polyacrylonitrile remaining 10% are made from rayon or petroleum pitch All of these materials are organic polymers, characterized by long strings of molecules bound together by carbon atoms

The Manufacturing Process Part Chemical and Part Mechanical Spinning Stabilizing Carbonizing Treating the surface Sizing

Carbon-Fiber Advantages Disadvantages Very low weight High impact tolerance Insensitive to temperature Reduced maintenance costs Long service life Disadvantages Oxidize readily between 600-700 C Very Expensive Complicated to produce High electrical conductivity of graphite particles

Ti-Carbon Fibre Bonding Using Adhesive Ion bean enhanced deposition

Applications Defense applications such as tank shields, Fighter plans. Aerospace applications Aircraft Applications Automotive applications

Future work Captain America’s Shield Wolverines Claw Body Armour

Questions