In the previous installment on mechanical materials, we introduced the differences between chemistry and mechanical materials, and the first half of the main classifications of mechanical materials.
This time, we'll start from the part that wasn't explained in the previous classification.
Before we begin, let's briefly review what we covered last time: The biggest difference between chemistry and mechanical materials is..."The study of how humans can utilize materials."That was the point.
In chemistry, the focus is mainly on learning the scientific properties of materials and the phenomena that occur, rather than how humans use them. In contrast, mechanical materials science involves learning about materials in a way that is more familiar to us.
As a review of classification, materials are typically arranged in order of their physical and chemical properties, similar to the periodic table learned in chemistry. However, in the classification of mechanical materials, materials are classified in a way that is convenient for humans to use.
Therefore, as a general classification, materials can be divided into metals and nonmetals.
I explained that metals are classified into iron and non-ferrous metals based on their historical use by humans and the amount of know-how accumulated over time.
That was a review, and now we'll continue from where we left off last time, introducing the main materials that are classified as nonmetals.
Nonmetallic materials for machinery
Now, let's look at the classification of nonmetallic materials.
As shown in the diagram, nonmetallic materials can be broadly divided into two categories: organic materials and inorganic materials.
Well, I imagine that many people would honestly say, "I don't really understand what organic materials and inorganic materials mean," so let me explain each material in an easy-to-understand way.
organic materials
As far as I know, there is no clear definition of what constitutes an organic material, but generally, it is referred to as "a material whose constituent substances are mainly carbon (C), hydrogen (H), oxygen (O), and nitrogen (N)."
In terms of materials familiar to us, plastics and rubber are typical examples that everyone knows.
I apologize for speaking from my own perspective, but a simple, broad classification approach would be:You can think of all materials made from petroleum as organic materials.
Petroleum itself is essentially a mass of hydrocarbons, as shown in the following diagram, and is therefore composed of carbon (C) and hydrogen (H), which are the very elements that define organic materials.
As you probably learned in social studies, petroleum extracted from the Earth is a mixture of various chemical bonds and impurities, so it undergoes a process called distillation to transform it into substances that are easier for humans to use, such as gasoline, diesel fuel, and naphtha.
Naphtha, found in this material, is used as a raw material to produce various resins and synthetic rubbers.
Other examples of organic materials, though I'm not very familiar with them, include the bodies of living organisms, which are also classified as organic materials (such as proteins).
Here, I'd like to share a little anecdote about the dawn of organic materials science, which I think many people already know but which I found interesting.
The Dawn of Organic Materials
First of all, the concept and definition of organic materials have existed since ancient times, and until around 1800 AD, they were considered substances produced by the mysterious forces of life and were thought to be impossible to produce artificially.
It seems that humankind has always had a considerable interest in materials, and has been studying the technique of alchemy since ancient times (it has existed throughout recorded history).
The ultimate goal of alchemy has been several, but some of the most representative have been to transform ordinary materials such as stones and soil found lying around into precious and valuable gold through mysterious magic, or to create artificial life forms like homunculus.
However, despite numerous geniuses (including famous figures like Newton) working on it for over 2000 years since ancient times, there was absolutely no sign of being able to create gold or a homunculus, so it was common knowledge that they were impossible to create.
In the 20th century, it became clear that one of the targets, gold (Au), being an atom, could never be created through normal chemical processes (it could be created by colliding protons or neutrons with each other in a super-large accelerator and then causing isotopes to beta decay).
As for the other target, a substance like a homunculus, unlike gold, a groundbreaking discovery of the century was made by chance in the early 19th century.
Then, in 1828, Friedch Wöhler of Germany accidentally created organic matter artificially.
I don't know if it's true or false, but I've heard the following anecdote.
When Wieler was 28 years old, he was conducting an experiment involving ammonium cyanate for a research assignment at the university where he was studying abroad. He was so exhausted that he left the flask containing the ammonium cyanate on top of the heater and fell asleep.
When Viera woke up in the morning, he discovered that a strange, white, sticky substance had formed that wasn't what he had intended.
What's remarkable about Wieler is that instead of simply dismissing it as a failure, he investigated what had been produced and discovered it was urea, an organic substance.
This marked the dawn of organic chemistry.
Many people may associate urea with urine, but it is a valuable organic substance that is still used in skin moisturizing creams and organic chemical fertilizers.
Science and technology are like thisWhen a critical discovery is made, development progresses exponentially, and organic materials have also developed explosively to the point where it is now impossible to live without using organic materials.
in this wayFailure is not something one intentionally seeks, but it is a classic example of how how one responds to failure can greatly change one's future.
I've strayed quite a bit from the topic, but I think learning history, science, and technology together is interesting and deepens understanding, so I will continue to explain things I know, interspersed with anecdotes.
Later, we will explain in detail the organic materials commonly used in machinery, such as plastics and rubber.
Next, let's discuss inorganic materials.
Inorganic materials
I will now explain the meaning of inorganic materials, but this definition is quite difficult to understand and rather terrible.
In chemistry, it is defined as "a material composed of inorganic nonmetallic substances excluding metals," and even in explanations considered easy to understand, it is described as "a substance excluding organic materials and metals."
I'm not confident I can give a clear explanation, but inorganic materials are "materials composed of common, readily available substances that are not of biological origin."
For example, many of the stones, soil, and gravel lying around are composed of silicon (Si) and are excellent inorganic materials.
The materials created by mixing soil and gravel lying around with water and other substances become familiar building materials such as cement and bricks.
A familiar example of a material used in tools is ceramic, which is used in pottery (Setomono). This is a fairly familiar inorganic material that has been used as a vessel since ancient times.
Other expensive ornaments such as diamonds, rubies, sapphires, and glasswork are also made from inorganic materials.
Unlike gold, which is an atom, these are inorganic materials and can be produced artificially relatively easily.
Diamonds are simply substances with an unusual arrangement of carbon (C) atoms, and the main constituent materials of rubies and sapphires are alumina or aluminum oxide (Al2O3), which can be described as rusted aluminum (glass is mainly silicon dioxide SiO2).
These expensive ornamental artifacts are very useful materials in engineering; diamonds (diamond cutters) are often used in cutting tools, and sapphires and rubies, being very hard materials, are often used to protect smartphone lenses and touch panels (ruby coating, sapphire coating).
Incidentally, although they are rarely recognized as having great value, diamonds, rubies, and sapphires for decorative purposes are sold by material manufacturers and anyone can buy them (though they are not that cheap).
moreoverCutting-edge inorganic materials include semiconductors, which are the basis of most smartphones and computers that you own.
Just like organic materials, inorganic materials are essential materials indispensable to our modern lives.
Well, inorganic materials are a field that has been deeply studied throughout history, especially through alchemy, so humanity possesses just as much know-how about them as it does about the metal iron.
I will explain ceramics, an inorganic material commonly used in machinery, in more detail later.
This covers the general classification of mechanical materials, but there is a new field (classification) of materials that has been developing rapidly and explosively recently, so let me introduce it.
composite material
The classification of these explosively developing materials is called composite materials, which essentially means "materials made by combining multiple substances that have been described so far."
The advantage of this composite material is that, until nowBy combining the best features of the substances described, it has become a material that is even more useful to humans.
A composite material that has been used since ancient times is straw brick, which is made by mixing mud and straw and drying it.
Plywood, which was commonly used a little while ago, is also a fine composite material made by gluing together several types of sheet-like wood.
A familiar modern example of a composite material is reinforced concrete, which is made by combining iron rods and solidifying them with concrete.
As these examples show, while bricks made solely from straw are not suitable building materials, mixing them with mud creates easy-to-use blocks. Similarly, with reinforced concrete, strong steel is added to the brittle and easily crumbling concrete, eliminating the shortcomings of each material and making them more useful.
It has become quite common recently.FRP (Fiber Reinforced Plastics) is a composite material made by solidifying fibrous (thread-like) carbon or glass (silicon) with plastic.
FRP is a highly versatile method for producing composite materials, and many types are made using various fibers.
For example, they use Kevlar fibers or aramid fibers, so it's a free-for-all situation where whoever does it first wins.
Common examples of its use range from sports equipment like fishing rods and tennis rackets to bathroom tiles and even bulletproof vests for weapons.
Among these, carbon is particularly usedFRP, also known as CFRP (Carbon Fiber Reinforced Plastics), is widely used in many industrial fields, most notably in the automotive industry.
Furthermore, when CFRP is baked in a kiln to turn the plastic into carbon, it becomes C/C material (Carbon-Carbon Composite), which in Japanese is called carbon fiber carbon reinforced composite material, and Japan quietly possesses the most advanced technology in this field.
This C/C material is well-known for its use in things like F1 car bodies and rocket heat-resistant panels.
in this wayIt's an incredibly convenient composite material, but it has a major drawback: it's extremely expensive because it's very labor-intensive to manufacture.
This is a classic example of a product that is high-performance but therefore expensive.
Due to its high price, it is often used in high-priced, high-performance products or one-off items (such as rockets), and it is still difficult for it to become widely available to the general public (is it common enough?).
SoAlthough composite materials have been used since ancient times, they are still in their developmental stages, and significant future advancements (from a designer's perspective, cost reduction being the most important factor) are expected.
Incidentally, many of these composite materials are not registered under industrial standards such as JIS, and each company often has its own unique know-how, so they often lack a common name and their product name becomes the material name.
Therefore, when researching, I think it's best to talk directly to the manufacturer.
Furthermore, composite materials are broadly classified by their base material: resin-based composites if the base material is resin, metal-based composites if the base material is metal, ceramic-based composites if the base material is ceramic, and graphite-based composites if the base material is carbon. However, you don't need to worry too much about this distinction.
I have used several composite materials, and I will share my experiences later.
Summary
This concludes our general explanation of the broad classification of mechanical materials, so let's summarize.
Mechanical materials are divided into metals, nonmetals, and composite materials.
Nonmetallic materials are divided into organic materials and inorganic materials.
Organic materials are mainly composed of carbon, hydrogen, etc., and typical examples include plastics and rubber.
Inorganic materials are composed of substances other than metals and organic materials, and ceramics are a typical example of such materials.
Composite materials are materials made by combining multiple different substances, and while they offer very high performance, they are also expensive.
Becomes
The overall picture is a bit complex, but it looks like this:
Well, I think it's enough if you've grasped the general overview of the materials used in mechanical engineering by now.
Details about each material and how to use them will be explained in detail after you have a basic understanding of mechanical materials.
From the next lesson onwards, we will begin to explain the fundamental theories of mechanical materials in earnest.
The first theory I will introduce will explain atomic structure.
To those who found this article helpful in understanding design:
While there is basically no textbook covering this content, and it is my own original work, I will introduce the textbook that I have been using since I was a student.
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