What is metallic glass? - Ashwini Bharathula

譯者: Mingyu Cui 審譯者: Max Chern

Steel and plastic.

鋼鐵和塑膠，

These two materials are essential to so much of our infrastructure and technology,

這兩種材料對於基礎設施 和科學技術都很重要，

and they have a complementary set of strengths and weaknesses.

並且他們有互補的優點和缺點。

Steel is strong and hard,

鋼鐵既堅固又硬，

but difficult to shape intricately.

但很難做出複雜的造型。

While plastic can take on just about any form,

塑膠可塑造成任何形狀，

it's weak and soft.

但既脆弱又軟。

So wouldn't it be nice if there were one material

所以該有多好啊？── 如果有一種材料

as strong as the strongest steel

能像最強鋼鐵一樣堅硬，

and as shapeable as plastic?

又像塑膠那樣可塑造的話。

Well, a lot of scientists and technologists

很多科學家和技術人員

are getting excited about a relatively recent invention called metallic glass

都為一個最近的發明感到興奮 ──「金屬玻璃」，

with both of those properties, and more.

它兼具這兩種性能，甚至更多。

Metallic glasses look shiny and opaque, like metals,

金屬玻璃看起來有光澤且不透明， 像金屬一樣，

and also like metals, they conduct heat and electricity.

同時也像金屬一樣可導熱和導電。

But they're way stronger than most metals,

但它們比大多數金屬堅硬很多，

which means they can withstand a lot of force

這意味它們可承受很大的力量，

without getting bent or dented,

也不會被折彎或凹陷，

making ultrasharp scalpels,

可製成超銳利的手術刀、

and ultrastrong electronics cases,

超堅硬的電子產品外殼、

hinges,

鉸鏈、

screws;

螺絲釘；

the list goes on.

還不止於此。

Metallic glasses also have an incredible ability

金屬玻璃還有一種極好的性能，

to store and release elastic energy,

能儲備及釋放彈性能量，

which makes them perfect for sports equipment,

使它們成為 製作體育用品的最佳選擇，

like tennis racquets,

比如網球拍、

golf clubs,

高爾夫球桿

and skis.

和滑雪板。

They're resistant to corrosion,

它們不易腐蝕，

and can be cast into complex shapes with mirror-like surfaces

且可被鑄成具有鏡面的複雜造型，

in a single molding step.

只需一個鑄造步驟。

Despite their strength at room temperature,

儘管它們在常溫下很堅硬，

if you go up a few hundred degrees Celsius,

如果把溫度升到攝氏幾百度，

they soften significantly,

它們會明顯地變軟，

and can be deformed into any shape you like.

並可塑造各式各樣你喜歡的形狀。

Cool them back down,

當把它冷卻下來，

and they regain the strength.

就會恢復之前的強度。

So where do all of these wondrous attributes come from?

這所有奇妙的特性是從哪裡來的呢？

In essence, they have to do with metallic glass' unique atomic structure.

實質上，這是和金屬玻璃 獨特的原子結構有關。

Most metals are crystalline as solids.

多數的金屬在固態時是結晶體，

That means that if you zoomed in close enough to see the individual atoms,

意思是如果把它放大到 可以看到每個原子，

they'd be neatly lined up in an orderly, repeating pattern

它們呈現有序、循環的整齊排列，

that extends throughout the whole material.

整個原料都是如此排列。

Ice is crystalline,

冰是晶體，

and so are diamonds,

鑽石及鹽也是。

and salt.

If you heat these materials up enough and melt them,

如果你將這些原料加熱到融化它們，

the atoms can jiggle freely and move randomly,

原子便可自由晃動且任意移動。

but when you cool them back down,

但當你把它們冷卻下來，

the atoms reorganize themselves,

原子便自己重新排列，

reestablishing the crystal.

重組為晶體結構。

But what if you could cool a molten metal so fast

但如果你能將融化的金屬快速降溫，

that the atoms couldn't find their places again,

快到原子們找不到它們應在的位置，

so that the material was solid,

此時，原料雖然是固體，

but with the chaotic, amorphous internal structure of a liquid?

但卻擁有液體的 混亂、非結晶的內在結構，

That's metallic glass.

這便是「金屬玻璃」。

This structure has the added benefit of lacking the grain boundaries

這種結構有另一個優點── 沒有晶粒邊界。

that most metals have.

多數金屬有晶粒邊界。

Those are weak spots where the material is more susceptible to scratches

晶粒邊界是原料較容易刮傷 或腐蝕的脆弱點。

or corrosion.

The first metallic glass was made in 1960 from gold and silicon.

第一個金屬玻璃是在1960年 由金和矽做出來的。

It wasn't easy to make.

這並不容易。

Because metal atoms crystallize so rapidly,

因為金屬原子結晶極為迅速，

scientists had to cool the alloy down incredibly fast,

科學家必須把合金急速冷卻，

a million degrees Kelvin per second,

一百萬開氏度每秒（降溫速度）

by shooting tiny droplets at cold copper plates,

藉著把微粒水珠射向冷銅片

or spinning ultrathin ribbons.

或做出超細的金屬絲。

At that time, metallic glasses could only be tens or hundreds of microns thick,

那時，金屬玻璃只能做成 幾十或幾百微米厚 (µm)，

which was too thin for most practical applications.

因太薄而不切實用。

But since then, scientists have figured out

但是自此，科學家便發現

that if you blend several metals that mix with each other freely,

如果將幾種容易混合的金屬互相摻雜，

but can't easily crystallize together,

由於它們的原子大小極不相同， 致使不易結晶在一起，

usually because they have very different atomic sizes,

the mixture crystallizes much more slowly.

這混合物的結晶速度就變慢許多。

That means you don't have to cool it down as fast,

這意味不需要那麼快速降溫，

so the material can be thicker,

所以材料可以比較厚，

centimeters instead of micrometers.

可達幾厘米厚 (cm) 而非微米 (µm)。

These materials are called bulk metallic glasses, or BMGs.

這種材料稱為「大塊金屬玻璃」，或BMGs。

Now there are hundreds of different BMGs,

現在已有幾百種不同的BMGs，

so why aren't all of our bridges and cars made out of them?

但為什麼不是所有的橋和車 都用這些材料製做呢？

Many of the BMGs currently available are made from expensive metals,

目前許多可用的BMGs 都是用昂貴金屬做的，

like palladium and zirconium,

比如鈀和鋯，

and they have to be really pure

它們必須很純，

because any impurities can cause crystallization.

因為任何雜質都會導致結晶。

So a BMG skyscraper or space shuttle would be astronomically expensive.

所以用 BMG 建摩天大樓或太空梭， 造價都是天文數字。

And despite their strength,

儘管它們堅硬，

they're not yet tough enough for load-bearing applications.

但還不夠堅硬到足以做承重類的應用。

When the stresses get high, they can fracture without warning,

當壓力很大時， 它們會毫無預警地折斷，

which isn't ideal for, say, a bridge.

對於例如橋之類，並不理想。

But when engineers figure out how to make BMGs from cheaper metals,

但是如果工程師想出 如何用更便宜的金屬製造 BMGs，

and how to make them even tougher,

以及如何讓它們更堅硬，

for these super materials,

那麼這些超級材料

the sky's the limit.

真是潛能無限啊！