Materials process chapter 2

What are functions of additional ingredients in silicon oxide solutions

1. Promoting fusion during heating 2. Increasing fluid he in molten glass 3. Retarding Divinci vacation (crystallizing in glass state) 4. Reducing thermal expansion 5. Improving chemical resistance 6. Adding color 7. Altering the index of refraction

Name the three groups of superalloys according to their base metal

1.Iron-based(Can be less than 50%) 2.Nickel based(Principally alloyed with chromium or cobalt) 3.Cobalt based(About 40 to 50% cobalt and 20 to 30% chromium) All of these are high-performance metals with high tensile strength, hot hardness, creep resistance, and corrosion resistance.

What temperature is delta phase

1394°C

Synthetic rubbers

3x tonnage of natural rubber Made of mostly petroleum Some rubbers: Butadiene (BR) Butyl (neoprene) Ethylene propylene Polyurethane Styrene-butadiene(40% of all rubber)

Composites

4th general category of materials. A material system composed of two or more physically distinct phases who's combination produces aggregate properties that are different from the ones the materials that make up the composites have.

What percentage of metal tonnage does steel and cast-iron take up

85%

What temperature is gamma phase

912°C This phase is important in designing heat treatment processes

What is a composite

A material system composed of two or more physically distinct phases who is combination produces aggregate properties that are different from those of its constituents. As in, We have combined the base materials, Metals ceramics and polymers, together to get a better material.

What is a cermet

A metallic matrix material with ceramic as the dominating phase in the mixture. An example is cemented carbides.

What is a polymer

A synthetic material (except for natural rubber) made of long chains of molecules. Most rubber products are made by a solidification process.

What are important applications of fiber reinforced plastics

Aerospace (Boeing 787) Automotive body panels Sports stuff (boat hulls, fishing rods, rackets, helmets, skis)

What are the three phases of iron

Alpha phase(Ferrite) Gamma phase (Austenite) Delta phase

What are some weaknesses of ceramics that might be corrected in fiber reinforced ceramic matrix composites

Although these have not been totally successful, ceramic matrix fiber composite try to correct: low toughness Low bulk tensile strength susceptibility to thermal cracking

What are abrasives typically made out of

Alumina and silicone carbide. Luminal is more used since it gives better results with grinding steel.

What is in feldspar

Aluminum silicate combined with either potassium, sodium, calcium, or barium

What is the solubility of carbon in steel

At the higher end of Alpha phase(723°C) it is 0.022% In gamma phase at 1130°C solubility is 2.1%

Why is austenitic stainless steel call by this name

Because it is in the austenite phase at room temperature. It also contains 18% chromium and 8% nickel. It has austenite structures from cryogenic temperatures to melting point temperatures.

What class of composite are cemented carbide

Because these are part of the cermets, cemented carbides are metallic matrix composites.

What is the chemical formula of ethylene the monomer for polyethylene PE (the most common plastic)

C2H4

Cemented carbide

Carbide compound bound in metallic matrix. Metallic binders are cobalt a nickel. Carbide ceramics constitute principal ingredient in cement to carbides. Tungsten carbide for cutting tools. Titanium carbide for high temp applications nozzle beans, bell seeds, thermocouple protection tubes, hard-working spinning tools.

What are applications of zinc

Casting(it has a low melting point) Galvanizing/coating Brass alloys Mass production automobiles and appliances Pennies

What are linear polymers

Chains of macromolecules produced by polymerization. This is the characteristic structure of thermal plastic polymer.

What is the most common alloy to create stainless steel

Chromium Chromium is typically greater than 15% of the alloy. This creates a thin impervious oxide film to resist corrosion. Another element would be nickel. We must have low carbon because it reacts with chrome to make chromium carbide which lowers corrosion resistance.

What is one of the most important applications of titanium nitride

Coating cutting tools. It has high hardness, good wear resistance and low coefficient of friction with ferrous metals. But unlike the other nitrides it is electrically conductive.

How do thermoplastic elastomers differ from conventional rubbers

Commonly used in footwear, rubber bands, and wire coating these are thermoplastics that behave like elastomers. They are not chemically cross-link but they have physical connections between soft and hard phases of incompatible substances that make up the material. Cannot be used in tires.

Cermet

Composite where ceramic is contained in metallic matrix. Finding enhanced through slight solubility at elevated temperatures. Important category is cemented carbide

What are the alloy elements for bronze

Copper and tin. Typically there is 10% tin.

What are the alloy elements for brass

Copper and zinc. Typically zinc is about 35% of the material.

What is the most important engineering property of copper that determines most of its applications

Copper has low electrical resistance and is abundant in nature so it is commonly used in electrical devices. It is also corrosion resistance (because it is a noble metal) and has high thermal conductivity

What are typical applications of cemented carbide WC-Co

Cutting tools, wire drawing dies, rock drilling bits and other mining tools, dies for powder metallurgy, and indenters for hardness tester's, and other applications where wear resistance and hardness are critical

How is cross-linking (curing or setting) accomplished

Depending on the starting ingredients the three ways are temperature activated systems(heat applied), catalyst activated systems(additive to liquid), or mixing activated systems(two main ingredients react to one another)

Fiber reinforced polymers

Embedded with fibers in matrix is usually thermoset like polyester or a epoxy sometimes thermoplastic polymers or elastomers are also used. Early for him made by stacking and binding in layers of fiber and polymers to desired thickness Applications: aerospace, military and commercial aircraft (fuselage, wings, tail, door, and interior), automotive body panels, boat hulls, tennis rackets, Golf club shafts, football helmets, Bows and arrows, skis, and bicycle wheels

What are the two major groups of metals

Ferrous metals And nonferrous metals The former contains iron(like steel and cast iron) and the latter does not... and that's the difference.

What are the common forms of the reinforcing phase in composite materials

Fibers, Flakes and particles Please take the load with the first phase deforms too far.

Where do we get silica

From quartz, and quartz is from Sandstone

Foam extender materials

Gas bubbles imbedded in polymer matrix. Styrofoam and polyurethane. Near zero density of gas plus low-density of matrix makes things extremely light weight. Guess also makes insulator for heat.

What is silica use for

Glass (A principal component) Whiteware Refractories Abrasives

What is most common as fibers in fiber reinforced plastics

Glass (in particular e-glass) Others are carbon, Kevlar, boron, silicone carbide, alumina and steel.

What distinguishes glass from new and traditional ceramics

Glass has a non-crystalline structure which causes it to be vitreous (clear and glassy). Silicon oxide is used widely because it naturally becomes glassy upon cooling from liquid. The term glass can also be a state of matter where the material is amorphous or noncrystalline.

) high strength Greater than 6.7%

Greater than 6.7%

What is the highest strength copper alloy

Heat treated beryllium - copper which is used for springs

Fiber reinforced metalmatrix composite

Hi tensile strength and modulus of elasticity in and low density so good strength to weight and stiffness to weight ratios. Typical metal: aluminum, magnesium, and 13 Fiber materials: boron, carbon, Al2O3, SiC

What are noteworthy properties of titanium

High strength to weight ratio Abundance Corrosion resistance High temperature strength (above 5500°C) Low thermal expansion

Important properties of fiber reinforced plastic composite materials

High strength to weight ratio High stiffness to weight ratio Low specific gravity

What are important properties of aluminum

High thermal and electrical conductivity Corrosion resistance Ductility/formabillity Low strength unless heat treated then it can compete with steel w/ high strength to weight ratio Abundant on earth Very affected by work hardening

Where is titanium carbide typically used

In high temperature applications

How are branched polymers formed

In polyethylene hydrogen atoms can be replaced by carbon atoms at random points initiating the growth of a branched chain at each location.

Fillers

Ingredients of secondary phase when used in polymer molding compounds. To categories: reinforcement, extenders Carbon black in rubber to increase strength and wear resist is ex of reinforcing category. Extenders increase bulk to reduce cost of polymers. Bubbles in foam are embedded in polymer matrix as extenders.

What are noteworthy properties of magnesium

Is the lightest of structural metals Catches fire easily at room temperature Soft and lax strength but can be alloyed/heat treated to get strength comparable to aluminum

What is a ceramic

It is an inorganic compound that is found in abundance in nature. These are hard and brittle and commonly used in glass or clay.

What is the most common base mineral for clay

Kaolinite(Al2Si2O5(OH)4)

Identify some of the common alloying elements other than carbon in low alloy steel

Manganese 13 Nickel 20 Molybdenum 40 Chromium 50-51 Vanadium (Cr-Vandium 61) (Numbers represent a AISI - SAE designation)

What are fiber reinforced metal matrix composites

Materials that combine high tensile strength and modulus of elasticity of fiber with metals of low density that achieving good strength to weight and stiffness to weight ratio's. Metals are typically aluminum, magnesium, and titanium. Fibers are aluminum oxide, boron, carbon, and silicon carbide

What are three basic categories of composite

Metal matrix composites Ceramic matrix composites Palmer matrix composites

What are some properties that distinguish metal from ceramic and polymer

Metals are: ductile malleable Have luster electrically conductive thermally conductive

What is an alloy

Meterials composed of two or more elements, where at least one of which is metallic. These types of metals enhance strength, hardness and other properties.

Thermosetting polymers

Molecules are a highly crossed linked structure rigid, brittle, less soluble, high service temps, not capable of remelting. The highest used thermosetting plastic is only 20% of highest used thermoplastic, polyethylene.

Natural (vulcanized) rubber

Mostly polyisoprene From latex which is milk from plants (rubber tree) Cured using sulfur and heat Hi string, tear resistance, resilience to wear and fatigue Largest market is tires

What is the molecular structure of thermosets

Network structure This is a highly cross-linked polymer that is essentially one gigantic macromolecule

Does silicone carbide (SiC) occur naturally

No, it is produced by heating mixtures of sand and Coke to temperature is around 2200°C

Ways to set a thermoset

One, temperature Two, CataList Three, mixing activated systems (ingredients are mixed and react)

What is the primary polymer ingredient in natural rubber

Polyisoprene A polymer of isoprene which is derived from latex found in many plants like the rubber tree. Rubber is extracted from latex by removing the water.

Elastomers(rubber)

Possible to have 500% extension 2 categories Natural rubber Synthetic rubber

Composite properties

Pros Superior to most other materials alone Hi strength to weight and stiffness to weight Better fatigue properties Hi toughness No I'm corroding Can have a combo of properties not attainable in metal, ceramic, or poly alone Cons Can be anisotropic (varying measurements from different directions) Subject to chemical attack Expensive, processing slow and costly

At what temperature is alpha phase

Room temperature

Polymer matrix composites

Secondary candy fibers, powder, or flakes. Most important of three classes. Types: Plastic molding compound, rubber reinforced with carbon black, and fiber reinforced polymers Properties: high strength to weight, stiffness to weight ratio's. Low specific gravity. Weight 1/5 of steel but close to strength in fiber direction

What are some ingredients of ceramics

Silica Alumina Hydrous aluminum silicate (Kaolinite)

What are the most important nitrides

Silicon nitride Boron nitride Titanium nitride

Besides high carbon content what other alloying element is integral in cast-iron

Silicone at about 3% makes iron suitable for casting.

What is the basic molecular structure of a polymer

Small molecules called monomers like ethylene are held together by covalent bonds. They join to form macromolecules which are very large molecules that chain together to form the polymer.

What are some important applications of nickel

Stainless steel Plating metal like plane carbon steel Good for corrosion resistance at high temperatures

What is the difference between traditional and new ceramics

The main difference between these is the way they are processed. The distinction is hard to make because aluminum oxide and silicone carbide are used in traditional and new ceramics. One tell of new ceramics is that they are usually chemically simpler than traditional ceramics

What is clay

The most widely used raw material in ceramics. It consists of fine particles of hydrous aluminum silicate that becomes a plastic substance that is formable when mixed with water. It is commonly based in mineral kaolinite

If elastomers and thermosets are both cross-linked why are they different

There is considerably less cross-linking in elastomers than in thermosets

What kind of polymer is nylon

Thermoplastic It is the most important member of the polyamide family which are strong, highly elastic, tough, abrasion resistant, and self lubricating.

What are the three categories of polymers

Thermoplastics Thermosetting palmers Elastomers

What is the difference between thermal plastic and thermoset

Thermosets are more rigid and brittle, less soluble in common solvents, capable of high service temperatures and they cannot be remelted after they are cold. Thermoplastics have low stiffness and strength, low hardness but high ductility and can be re-melted without any degradation of the material.

What are refractory ceramics

These are materials with high temperature resistance, thermal insulation and Glo chemical reactivity with the materials being melted in them. Typically alumina is used to form bricks for crucibles and furnaces to heat or melt materials.

What is the structure of thermoplastics

These are simply linear polymers(Without branches or cross-linking)

Identify characteristic properties of composite

These have superior properties than their ingredients by themselves: High strength to weight ratio, High stiffness to weight ratio (several times aluminum or steel) Better for fatigue properties High toughness Some do not corrode

How do properties of polymers compare to metals

They are cheaper than metals on a volumetric basis In volume, polymers generally require less energy to produce because working/forming temperatures are much lower for polymers

How do Fiber reinforced plastics compare to steel

They have 1/5 the weight yet strength and modulus are comparable in the fiber direction

What is the molecular structure of an elastomer

This is a lately cross-linked structure

What is anisotropic

This means we have different measurements of properties like strength or ductility from different angles of a material. For example looking parallel to fibers we have a much higher strength than perpendicular to fibers.

What are the three categories of ceramics

Traditional New ceramics Glasses

Where does alumina, an important raw material for traditional ceramics, come from

Typically bauxite but it can come from corundum which is a less common mineral that contains massive amounts of alumina

Ceramic matrix composites

Very difficult to make and not very successful. Consist of ceramic primary phase embedded with secondary phase, mostly fibers. Chemical compatibility with constituents in CMC's present difficulties. Ceramics used: alumina, for an carbide, boron nitride, silicone carbide, so good night tried, and titanium carbide and several glasses Fibers used: carbon, SiC, Al2O3

What is cross-linking

When a chain of macromolecules has branches sometimes primary bonding occurs between branches and other molecules which become cross-linked polymers. This happens because a portion of monomers are capable of bonding to adjacent monomers on more than two sides.

Where is feldspar used

When mixed with silica and clay it is used in stoneware, China, and other tableware.

How are superalloys hardened

With precipitation Particles that act to block the movement of dislocation and thus strengthen the metal