What is metallic glass? - Ashwini Bharathula

翻译人员: Emma Gao 校对人员: Mingyu Cui

Steel and plastic.

钢铁和塑料，

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

这两种材料对于基础设施和科学技术都很重要，

and they have a complementary set of strengths and weaknesses.

并且他们有互补的优点和缺点。

Steel is strong and hard,

钢铁又硬又坚韧，

but difficult to shape intricately.

但是却很难塑造出复杂的造型。

While plastic can take on just about any form,

塑料很容易被塑造成各种形状，

it's weak and soft.

但是又脆又软。

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

所以，如果这个世界上有一种材料

as strong as the strongest steel

能像钢铁一样坚硬

and as shapeable as plastic?

又能像塑料一样容易塑形，那该多好？

Well, a lot of scientists and technologists

因此，很多科学家和技术人员

are getting excited about a relatively recent invention called metallic glass

都为一个新发明而感到兴奋－－金属玻璃，

with both of those properties, and more.

它同时拥有这两个优点！

Metallic glasses look shiny and opaque, like metals,

金属玻璃看着像金属一样闪闪发光，并且不透明，

and also like metals, they conduct heat and electricity.

同时还可以像金属一样导热和导电。

But they're way stronger than most metals,

但是它要比大多数金属坚硬得多，

which means they can withstand a lot of force

这也就意味着它们可以承受很强的力，

without getting bent or dented,

却不会被折弯或折断，

making ultrasharp scalpels,

所以它们可以被用来制作超锋利的手术刀、

and ultrastrong electronics cases,

超耐摔的电子产品、

hinges,

铰链、

screws;

螺钉，

the list goes on.

它可以制作的东西还不止于此。

Metallic glasses also have an incredible ability

金属玻璃还有一个超牛的本领

to store and release elastic energy,

它可以储备并且释放弹性势能，

which makes them perfect for sports equipment,

这个优点让它们成为制造体育用品优越的材料。

like tennis racquets,

比如网球拍、

golf clubs,

高尔夫球杆

and skis.

和雪杖。

They're resistant to corrosion,

它不易被腐蚀，

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

并且可以塑造出有着光滑表面的复杂造型。

in a single molding step.

而这些，仅仅需要模具塑形。

Despite their strength at room temperature,

尽管它在常温下很坚韧，

if you go up a few hundred degrees Celsius,

如果你把它放在几百度的高温下

they soften significantly,

它便能很快的变软，

and can be deformed into any shape you like.

并且塑造出各种各样你喜欢的形状。

Cool them back down,

当把它冷却下来，

and they regain the strength.

就又会恢复之前的强度。

So where do all of these wondrous attributes come from?

它的这些奇妙之处都从哪里来的呢？

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

从本质上来看，这些都归根于它奇特的分子结构。

Most metals are crystalline as solids.

大多数金属都是晶体般的的固体结构，

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

这也就意味着当你把它放在显微镜下放大去观察它的分子结构，

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

分子是整齐地周期性排列着的，

that extends throughout the whole material.

排满整块金属。

Ice is crystalline,

冰、

and so are diamonds,

钻石、

and salt.

还有盐，都是晶体。

If you heat these materials up enough and melt them,

如果你把以上这些加热并且融化，

the atoms can jiggle freely and move randomly,

他们的分子就被释放出来并可以自由移动，

but when you cool them back down,

但当你再一次把它冷却下来，

the atoms reorganize themselves,

这些原子便自发的重新排列起来，

reestablishing the crystal.

重新变成晶体结构。

But what if you could cool a molten metal so fast

但是如果你可以很快地融化这些金属，

that the atoms couldn't find their places again,

快到原子们找不到它们应在的位置，

so that the material was solid,

那么这时，金属虽然变成了固体，

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

但是却拥有像液体一样混乱的非晶体结构。

That's metallic glass.

这便是金属玻璃。

This structure has the added benefit of lacking the grain boundaries

这种结构优点还有：它没有晶粒边界，

that most metals have.

大多数金属有晶粒边界。

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

晶粒边界是大多数金属最容易被刮破的脆弱的地方，

or corrosion.

这些地方也容易被腐蚀。

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

【加州理工学院】 金属玻璃最初是由金子和硅在1960年做出来的。

It wasn't easy to make.

这并不容易。

Because metal atoms crystallize so rapidly,

因为金属原子结晶极为迅速，

scientists had to cool the alloy down incredibly fast,

所以科学家们必须极快地把合金冷却，

a million degrees Kelvin per second,

大概是以一百万开氏度每秒，

by shooting tiny droplets at cold copper plates,

他们把微粒射向冷铜片

or spinning ultrathin ribbons.

或者极薄的旋转带。

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

在那时，金属玻璃只能有几十或几百微米厚，

which was too thin for most practical applications.

这在应用中非常不切实际。

But since then, scientists have figured out

但是在那时以后，科学家们便发现

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

如果你将几种可以任意混合的金属混合在一起，

but can't easily crystallize together,

它们便很难在一起结晶，

usually because they have very different atomic sizes,

这往往归因于它们的原子大小不同，

the mixture crystallizes much more slowly.

它们的混合体结晶就慢了很多。

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

这也就意味着你不需要那么快降温，

so the material can be thicker,

所以最后得到的材料变得厚了很多，

centimeters instead of micrometers.

可以达到几厘米厚。

These materials are called bulk metallic glasses, or BMGs.

这种材料被叫做块状金属玻璃，或BMGs。

Now there are hundreds of different BMGs,

现在我们有几百种不同的BMG，

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

但是我们为什么不用他们做桥，做车呢？

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

已知的玻璃金属都是用昂贵材料做的，

like palladium and zirconium,

比如钯和锆，

and they have to be really pure

并且用的都是极纯净的金属，

because any impurities can cause crystallization.

因为任何杂质都会加速结晶。

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

所以不管是用玻璃金属制作摩天大楼还是航天飞机都过于昂贵。

And despite their strength,

尽管它们坚硬，

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

可它们的韧性还不足以做承重类的应用。

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

当压力很大的时候，它们容易毫无预兆地折断，

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

这对于造桥可并不理想。

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

但是如果工程师们可以想出怎么能用便宜的金属制造金属玻璃，

and how to make them even tougher,

同时也想出怎么能让它们的韧性变强，

for these super materials,

那么这些材料

the sky's the limit.

便把人类的极限推到了天界的尽头。