SECOND EXAM CHE 333 Second Exam Fall 2008

SECOND EXAM CHE 333 Second Exam – Fall 2008. Put your name on all pages of the exam- Bond, James 1. Describe “Age Hardening” of aluminum alloys. Detail both microstructure and mechanical property changes. Solution treat –a, quench – Supersaturated solid solution a, age – a+GP zones – under aged - weak, a+ q” peak aged optimum strength, a+ q’ – overaged -weaker. NO MARTENSITE. Hardness v time curve 2. What is an edge dislocation and what is a screw dislocation. Show a Burgers circuit is constructed and compare Burgers vectors for an edge and screw dislocation. Edge - b is 90 to dislocation line parallel to motion, screw – b is parallet to line 90 to motion, slip planes {111}<110> FCC, {110}<111> BCC, (0001)<1120> HCP, Shear stress moves them above elastic limit. 3. Describe how martensite is formed. What is a TTT and a CCC curve? How does alloying with Cr and Ni alter these curves? Only g to BCT martensite so quench from above 727 C to below Ms. TTT – time transformation curve, CCC – continuous cooling curve, Cr and Ni increase hardenability, moves curves to longer times. 4. What is a “tempered steel”? How do you get a spherodized structure in a steel? Tempered steel formed by heating a MARTENSITIC steel below eutectoid to form very small carbides to control mechanical properties. Spherodized – PEARLITCIC steel heated just below eutectoid for long time periods to produce large spheres of carbide – 650 C for 24 hours.

CHE 333 Class 17 Materials for Vampires “To nibble or not to nibble, that is the question” – Willy Shakespeare

LOCATION, LOCATION Top left – Whitby Abbey where Dracula landed in England. Bottom left and above – Robin Hoods Bay toward Ravenscar and alleys, inspiration for Bram Stoker writing Dracula.

MATERIALS FOR STOPPING DRACULA Wood – legendary choice – stake to the heart only solution that works. Other materials – garlic round neck – early bio-tech? Lightweight materials.

Wood Properties CHOOSE KILN DRIED HICKORY PECAN AS STRONGEST?

Wood Structure

Carbon Composite Properties Handle of light weight carbon fiber composite?

Carbon Fiber Composite Structure

Testing Adhesive Bonds Load to failure Lap shear testing conducted. Samples are stressed to failure and the failure stress recorded. Composite Adhesive Conversion Coating Metal

Adhesive Bonding Degradation Effect of marine exposure to joint strength for a carbon fiber composite to titanium bond Remember the human body fluids are salt containing.

Metal Matrix Composites Similar structure to carbon fiber composites and similar joining problems Continuous fibers – long: discontinuous - chopped strands Particulate – non thermodynamic phase, added to melt Carbon fiber composites are stronger.

Coatings Handle needs some grip!! Spray on coatings. Paints – polymers such as latex, with a particle such as sand for friction.

A LIGHTER FASTER DRACULA CLOTHING Mandatory Cape, black suit, white shirt and waistcoat – clothing, use polypropylene coated films, like chip packaging? Need to fly and be undetected so non magnetic materials, ie no ferritic steels. Protection from stake important. Light Armor Plate. Aluminum Alloy 2219? Kevlar and carbon fibers easily cut!!

Specific Properties Compared Specific properties are normalized with density, so weight is taken into account for the same volume.

Teeth - for a little nibbling Teeth – calcium based, not that strong. Ceramic better?

DRINKING UTENSIL Traditional Glass. Disadvantages • Brittle – fractures every time thrown into empty fireplace. • Difficult to decorate “fashionably” • Dishwasher safe? Plastic Container. Advantages. • Ductile - absorbs impacts without failure when thrown. • Can decorate easily by adhesive bonding so Dracula can show home crafting skills. ( Sell on Internet – business opp? ) • Light weight. • Many colors and shapes available.

PROTECTION OF POTENTIALVICTIMS BITE PROTECTION • Location known – neck region. • Hard Materials – overlapping double layer of ceramic plates, designed so joint in top layer covered by lower layer. Thickness, ie, teeth cannot get through material – reinforced composite 12. 5 mm thick to wear around neck. • Lightweight. • Coat decoratively with gold or a few diamonds

Conclusions Modern Materials would help both sides!!! Happy Halloween!!!.