# Ch 1: Materials & Properties in Engineering

### About This Chapter

## Materials & Properties in Engineering - Chapter Summary

This chapter can help you study important materials and properties used in engineering. You can learn about bulk density, hysteresis, yield point and more. The lessons in this chapter are accompanied by quizzes that test your comprehension of what you have learned in each lesson, and you get immediate feedback on these quizzes so your strengths and weaknesses will be quickly determined. This chapter can help you to:

- Calculating diffusion coefficient, bulk density, helix angles, and pitch
- Comparing types of friction
- Explain processes like hardening and the transformation of martensite
- Understand alloys, yield point and cleavage
- Explain the loop of hysteresis and the procedure for liquid penetrant testing
- Review the planes for cleavage

### 1. Diffusion Coefficient: Definition, Equation & Units

This lesson defines and explains the importance of the diffusion coefficient and shows the equation relating the diffusion coefficient to temperature.

### 2. Bulk Density: Definition & Calculation

In this lesson, we'll discuss bulk density, a property of soils. You'll learn the definition of bulk density as well as how to calculate it. We'll also explore the differences between bulk density and other types of density.

### 3. What is Fluid Friction? - Definition, Equation & Example

Fluid friction affects your everyday life from trying to squeeze honey into your tea to dictating how far you can drive on a tank of gas. Learn the difference between internal and external friction and what role each plays when working with a fluid.

### 4. What is Internal Friction? - Definition, Angle & Coefficient

In this lesson, we will learn about the internal friction force, the friction angle and the internal friction coefficient. We also review a practical example of a solid material like soil body to better understand the concept of the internal friction coefficient and friction angle.

### 5. What is Specific Volume? - Definition, Formula & Units

In this lesson, you'll learn what specific volume is, how to calculate it for ideal gases, and what units are associated. The lesson also includes numerical examples to better understand how the calculations are done.

### 6. Precipitation Hardening: Definition & Process

This lesson defines precipitation in solid materials and explains how precipitation hardening increases the hardness of materials by impeding dislocation motion.

### 7. Martensite: Definition, Transformation & Microstructure

This lesson defines martensite, explains the diffusionless austenite-to-martensite transformation, and describes microstructure and properties of martensite.

### 8. What is Hysteresis? - Definition & Loop

Hysteresis is a common phenomenon in physical systems and occurs when the system's output depends not only on its present inputs but also on past inputs (when the system exhibits memory so to speak). Learn more in this lesson.

### 9. Modulus of Rigidity: Definition & Equation

In this lesson, modulus of rigidity is introduced. First, we'll define the term modulus of rigidity, also known as shear modulus, then we 'll look at some equations and examples.

### 10. Yield Point: Definition, Curve & Elongation

Ever wondered why some things snap quickly and others can stretch before breaking? In this lesson, you will learn & explore the details that describe the physical phenomenon.

### 11. What is an Alloy? - Definition & Examples

Alloys are mixtures of metal with other metals or non-metals. This process gives the material more desirable properties, such as increased hardness and lower melting points.

### 12. Viscosity Index: Definition & Formula

Selecting the right lubricant for protecting your car's engine depends largely on the fluid's viscosity index. In this lesson, learn more about the viscosity index, its equation and significance.

### 13. Helix Angle: Definition, Formula & Calculation

This lesson defines a helix angle as applied to mechanical engineering, and describes a formula to calculate it. The key geometrical parameters for defining a helix are explained, and an example calculation is used to show how to calculate the helix angle.

### 14. Isotropy: Definition & Materials

This lesson defines isotropy and explains its importance. It also discusses both isotropic materials and anisotropic materials and gives several examples of each.

### 15. Modulus of Elasticity: Steel, Concrete & Aluminum

In this lesson, we are going learn about the modulus of elasticity, a property of materials, and we are going to look at some examples using the modulus of elasticity of steel, concrete, and aluminum.

### 16. Air Infiltration: Definition, Rates & Calculation

This lesson defines the term 'air infiltration' and provides an understanding of air infiltration rates. The lesson also covers the way air infiltration rates are calculated.

### 17. Poisson's Ratio: Definition & Equation

Poisson's ratio describes the relationship between strains in different directions of an object. It is a useful constant that tells us what will happen when we compress or expand materials.

### 18. Fick's First Law: Definition, Derivation & Examples

Fick's First Law states that diffusion in gases or fluids is driven by local concentration variations. Even though individual molecules move in a very erratic, random way, their overall diffusion is extremely predictable.

### 19. Coarse Aggregate: Definition & Density

Coarse aggregates are components found in many areas of the construction industry. They have structural uses such as a base layer or drainage layer below pavements and in mixtures like asphalt and concrete. This lesson explores the various types of coarse aggregates.

### 20. Base Metal: Definition & Types

Base metals might sound boring, but they don't have to be. In this lesson, you'll learn the names of many base metals as well as some cool tidbits about a few of them.

### 21. Internal Force: Definition & Examples

In this lesson you will learn what the internal forces are and what they do in a structure member such as pole, beam and column. We also review the commonly used sign convention and solve a numerical example to understand how to calculate an internal force in a structure member.

### 22. External Force: Definition & Examples

In this lesson, we are going to learn about external forces and their effects on the body to which they are applied. We are also going to distinguish external forces from internal forces.

### 23. Tare Weight: Definition & Calculation

In this lesson, you will learn what tare weight is and the formula that you would use to calculate it. Other terms, such as net weight and gross weight, will be reviewed so that each is clearly understood.

### 24. Tare Weight vs. Net Weight

In this lesson, you will learn the difference between tare weight and net weight, and how to apply each form of measurement. Gross weight will also be discussed to ensure that the differences between the three measurements are understood.

### 25. What is Concrete? - Composition & Use in Construction

In this lesson, we are going to learn about concrete, its components, and its use in construction. We are also going to talk about the mechanics of the materials in concrete.

### 26. Difference Between Concrete & Cement

The terms 'concrete' and 'cement' are often used interchangeably, but incorrectly so! This lesson clearly delineates the difference between the two, and explains how each is made.

### 27. Edge Dislocation: Definition & Motion

Some pieces of metal are able to deform more than others, even if the chemical makeup of the metal is exactly the same! What is going on? In this lesson, learn about edge dislocations and how they affect a metal's ability to stretch and change its shape.

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### Other Chapters

Other chapters within the Introduction to Engineering course

- Stress & Strain in Engineering
- Temperature & Heat in Engineering
- Tools & Processes in Engineering
- Pressure in Engineering
- Tolerance in Engineering
- Basics of Structural Engineering
- Basics of Chemical Engineering
- Electricity in Engineering
- Electrodynamics
- Physics Concepts in Engineering
- Acoustics in Engineering
- Building Construction & Properties in Engineering
- Electrical Interference in Engineering