manufacturing processes 1 chapter 1-4

Which sector contributes the largest percentage to the U.S GDP?

Service industries

What is the primary technological importance of manufacturing?

It provides the products that help society live better

Which type of manufacturing involves minimal or no waste material?

Net shape process

What type of products are included in “hard product variety”?

Products with substantial design differences

What is the key characteristic of thermoplastic polymers?

They can be reheated multiple times without altering molecular structure

What type of starting material is used in deformation processes?

Ductile solids

What is the purpose of property-enhancing operations?

Improve physical or mechanical properties

Which manufacturing process involves pressing and sintering?

Particulate processing

Which category of ceramics includes alumina (AI?O?)?

Crystalline ceramics

Which product variety has a minor design differences, such as between car models?

Soft product variety

What is an example of shaping operation?

Drilling

What is an example of mechanical assembly

Press fitting

Casting is an example of a ____ process

Solidification

What do primary bonds involve?

Exchange or share valence electrons

Which bond invokes atoms of one element giving up electrons to another element?

Ionic

What happens in covalent bonding?

Electrons are shared between atoms

Which bond type creates a general electron cloud that permeates the entire material?

Metallic

What type of bonds are secondary bonds?

Bonds between molecules

What is the characteristic of crystalline structure?

A geometric grouping of atoms that is repeated

Which type of crystal structure does aluminum have?

Face-centered cubic FCC

What is an example of an amorphous material?

Glass

What is a common imperfection in crystalline structures?

Grain Boundaries

What type of defect involves the edge of an extra plane of atoms in a lattice?

Edge Dislocation

What happens during plastic deformation?

Atoms are forced to move to new positions

How are polycrystalline structures formed?

Crystals nuclear at random orientations during solidification

What kind of materials have noncrystalline structures?

Amorphous solids

Which material typically has a body-centered cubic (BCC) structure at room temperature?

Chromium

Which of the following is a characteristic of ceramics?

High hardness and stiffness

What is a common property of polymers?

High electrical resistivity

What is the basic structural unit in crystalline materials?

Unit cell

What is the basic formula for engineering stress?

Force / original area

What is Hooke’s Law?

Stress is proportional to strain in the elastic region

What property does modulus of elasticity (E) measure?

Stiffness

How is true stress different from engineering stress?

True stress accounts for instantaneous area

What does ductility refer to?

Ability to plastically deform without breaking

Which of the following materials typically shows elastic-perfectly plastic behavior at high temperatures?

Metals above recrystallization temperature

In a compression test, how does the cross-sectional area change?

Increases

What happens in the plastic region of a stress-strain curve?

The material undergoes permanent deformation

What does a brittle material show in a tensile test?

Fracture with little plastic deformation

Which hardness test uses a cone-shaped indenter?

Rockwell

What property does hardness measure?

Resistance to permanent indentation

What is the term for a material’s ability to absorb energy before fracturing?

Toughness

What does the term “viscoelastic” behavior describe?

Time-dependent strain under stress

What is the effect of increasing temperature on metal ductility?

Increases ductility

What does the Brunel hardness test measure?

Resistance to indentation using a hard ball

What property is determined from the slope of the elastic region of the stress-strain curve?

Modulus of elasticity

What does yield strength indicate?

Stress at which material starts to deform plastically

What is true strain?

Natural logarithm of the ratio of the current length to the original length

Which test is used for brittle materials like ceramics?

Bending (flexure) test

What is the common method to estimate shear strength of a material?

Using tensile strength multiplied by 0.7

What does recrystallization in metals allow for during deformation?

The formation of new strain-free grains

The yield point in an stress-strain curve represents the start of _______.

Plastic deformation

Which of the following is a physical property of materials?

Thermal conductivity

Density is defined as:

Mass per unit Volume

Specific gravity of a material’s ability is defined as its density relative to:

Water

Thermal expansion measures:

Increase in length with temperature change

Which material property is affected by thermal agitation?

Diffusion

Melting point in alloys begins at the:

Solidus

Electrical conductivity is the inverse of:

Resistivity

Ohm’s Law

I = E / R

Which of the following is not a semiconductor material property?

Low resistivity

Which process does not involve melting?

Sintering

The energy required to accomplish the transformation from solid to liquid is called

Heat of fusion

What is used in shrink fit assemblies in manufacturing?

Thermal expansion

In electrolysis, the positive electrode is called the

Anode

Diffusion in manufacturing is used in

Surface hardening

In electrical properties, semiconductors are defined by their ability to

Alter conductivity in localized areas

Which material has a gradual transition from solid to liquid during melting point

Noncrystalline materials

During electrolysis, which ions move towards the cathode?

Positive ions

which process removes materials from a metal surface using electrical energy?

Electrochemical machining

Thermal diffusing is the ratio of

Thermal conductivity to volumetric specific heat

Electroplating is primarily used to

Coat a surface with a thin metal layer

In semiconductors, ____ is the most commonly used material due to its abundance and ease of processing

Silicone

Chemical change due to electrical current

Electrolysis

Movement of atoms due to thermal agitation

Diffusion