"I see, you use corundum instead of alumina.

Jin, who was listening nearby, was also impressed by this idea.

"No, it's not a very praiseworthy idea since it was developed during wartime when supplies were scarce," he said.

"No, it's not that bad," he said. ...... is a good thing, using what war has created for peaceful purposes."

"Yes, ...... it is."

"If we add some trace elements to the corundum, won't it enhance it even more?"

"What?"

What Jin said was a principle common to < materials, but apparently Arnold had never heard of it before.

"Why don't you try corundum with about one percent of mithril silver added?"

Jin asked Katya,

"We have enough materials in our laboratory for experiments.

He replied, "We have enough material in our laboratory to experiment with.

"All right, then, let's give it a try.

Eira suddenly became enthusiastic.

"Well, let's start with an experiment.

Gromma also suggested, and they went straight to the laboratory. Jin and Arnold are with them.

Reiko and Chelle followed, of course.

"First, corundum.

Transparent aluminum oxide crystals.

Specific gravity is about 4. Melting point is 2050 degrees Celsius.

Its Mohs hardness is 9, second only to diamond.

To this we add one percent by weight of mithril silver.

"<>"

Jin adds mithril silver by engineering magic.

"Oh."

"It's beautiful. ......"

Trace amounts of silver often have little effect on the color of minerals, but mithril silver seems to be a little different, resulting in pale lemon-colored crystals.

"I guess it was a one-shot success."

Jin, who is used to making this kind of Magi material, said to himself.

He decided to investigate the physical properties of < for the time being.

The default properties are almost the same as those of the original corundum.

This is to be expected.

The question is, how much enhancement by magic power is possible.

This < was done by Eira, not by Jin.

Eira did this , not Jin, because Jin might add a more powerful effect than usual.

"Hmm, this is quite ......"

"We're getting about five times the strength!"

That's good enough.

But the fracture properties ......

The hardness is sufficient from the start.

The problem is <>, i.e. <>.

Also, <> are important.

For example, when force is applied to a material, does it suddenly crack like glass when the limit is exceeded, or does it undergo irreversible deformation (plastic deformation)?

In the case of steel, there is an elastic limit, which is the limit beyond which the material will return to its original state if the force is stopped. If it exceeds this limit, it deforms like clay (plastic deformation) and remains bent even if the force is removed.

The desirable property of glass or iron depends on the application, but for the skeleton of a golem, the material that does not break down suddenly like iron, but rather is <, is considered to be more desirable.

"That would have to be metal, wouldn't it?"

"That's right."

"I think so too. However, isn't it strong enough?

Since it is not for combat use, it is unlikely that it will be subjected to a force greater than expected.

Therefore, Arnold said that if a sufficient safety factor is taken, it would be at a practical level.

Human bones break without bending.

"Indeed. Now all we have to do is foam it and reduce its specific gravity.

We can do that. Jin, Arnold, thank you!

Eira shook hands with Jin and Arnold with a big smile.

"No, no, I'm glad I could be of help.

Katya approached Arnold with a smile.

"Well, Mr. Arnold, perhaps there are some more techniques from the wartime that can be used today?

"Huh?　Oh, I see.

Arnold's face turned into a "what if" look.

Jin is also interested,

"That's certainly possible. Let's put it all together and make a report.

When I suggested this, Katya was very enthusiastic.

She said, "Yes!　Let's put it all together.

"You love this kind of thing, don't you, Katya?

With a wry smile, Eira sat down at the table.

"Great. I'd love to hear it."

And Gloma Tolley joined them.

"All right, let's get started.

Jin led the discussion.

"So, Arnold, what's your subject?

"I can't think of any ...... off the top of my head," said Arnold.

"Of course you can. How about an alternative for expensive or rare materials?

When Jin specified this, Arnold seemed to have an idea.

"Ah, there are two alternatives...one is adamantite."

"Huh?"

Adamantite is the hardest single metal in the world. It is also heavy.

It is produced in small quantities, so its use is limited. ...... except for the island of Horai.

"Carbon steel with a carbon content of 1.2 percent is quenched, and then multiplied by ."

"I see."

<

"With this, it will be about one-third to one-half of normal adamantite."

"The specific gravity of steel is about 7.9 and adamantite is 19.3, so in terms of strength per weight, it's a pretty good substitute."

"Yes, that's right. This is useful!

"Good."

Arnold was relieved that he could be of help.

The other one is the Magi Crystal.

"Oh, we're going to run out of those too, aren't we?"

"Yes. But I'll collect any kind of shavings, powder, fragments, or remnants that were attached to the original stone.

"You don't mean to make it into one, do you?"

Jin could use and to unite the pieces and then use to improve the quality, but that is not possible for everyone.

The main technology in wartime is something that relatively anyone (magecraftsman) can use.

"To make one, however, is to use <>. We harden those too small magic crystals with magic resin.

You don't use fusion?

"No, I don't. You may not be aware of it, but if you normally use <>, the crystalline structure will be severely disturbed.

"Then use <> and you'll get ...... and ......."

"Yes. <

"Is that what it is?"

"That's how it is."

Jin understood what Arnold was saying.

He listened to Arnold's explanation.