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什么是金属玻璃? – 译学馆
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什么是金属玻璃?

What is metallic glass? - Ashwini Bharathula

钢铁和塑料
Steel and plastic.
这两种材料对于基础设施和科学技术都很重要
These two materials are essential to so much of our infrastructure and technology,
并且他们有互补的优点和缺点
and they have a complementary set of strengths and weaknesses.
钢铁又硬又坚韧
Steel is strong and hard,
但是却很难塑造出复杂的造型
but difficult to shape intricately.
塑料很容易被塑造成各种形状
While plastic can take on just about any form,
但是又脆又软所以
it’s weak and soft.
如果这个世界上有一种材料
So wouldn’t it be nice if there were one material
能像钢铁一样坚硬
as strong as the strongest steel
又能像塑料一样容易塑形
and as shapeable as plastic?
那该多好?因此 很多科学家和技术人员
Well, a lot of scientists and technologists
都为一个新发明而感到兴奋--金属玻璃
are getting excited about a relatively recent invention called metallic glass
它同时拥有这两个优点!
with both of those properties, and more.
金属玻璃看着像金属一样闪闪发光
Metallic glasses look shiny and opaque, like metals,
并且不透明同时还可以像金属一样导热和导电
and also like metals, they conduct heat and electricity.
但是它要比大多数金属坚硬得多
But they’re way stronger than most metals,
这也就意味着它们可以承受很强的力
which means they can withstand a lot of force
却不会被折弯或折断
without getting bent or dented,
所以它们可以被用来制作超锋利的手术刀、
making ultrasharp scalpels,
超耐摔的电子产品、
and ultrastrong electronics cases,
铰链、
hinges,
螺钉
screws;
它可以制作的东西还不止于此
the list goes on.
金属玻璃还有一个超牛的本领
Metallic glasses also have an incredible ability
它可以储备并且释放弹性势能
to store and release elastic energy,
这个优点让它们成为制造体育用品优越的材料
which makes them perfect for sports equipment,
比如网球拍、
like tennis racquets,
高尔夫球杆和
golf clubs,
雪杖
and skis.
它不易被腐蚀
They’re resistant to corrosion,
并且可以塑造出有着光滑表面的复杂造型而这些
and can be cast into complex shapes with mirror-like surfaces
仅仅需要模具塑形
in a single molding step.
尽管它在常温下很坚韧
Despite their strength at room temperature,
如果你把它放在几百度的高温下
if you go up a few hundred degrees Celsius,
它便能很快的变软
they soften significantly,
并且塑造出各种各样你喜欢的形状
and can be deformed into any shape you like.
当把它冷却下来
Cool them back down,
就又会恢复之前的强度
and they regain the strength.
它的这些奇妙之处都从哪里来的呢?
So where do all of these wondrous attributes come from?
从本质上来看 这些都归根于它奇特的分子结构
In essence, they have to do with metallic glass’ unique atomic structure.
大多数金属都是晶体般的的固体结构
Most metals are crystalline as solids.
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
That means that if you zoomed in close enough to see the individual atoms,
分子是整齐地周期性排列着的
they’d be neatly lined up in an orderly, repeating pattern
排满整块金属冰
that extends throughout the whole material.

Ice is crystalline,
钻石、
and so are diamonds,
还有盐
and salt.
都是晶体如果你把以上这些加热并且融化
If you heat these materials up enough and melt them,
他们的分子就被释放出来并可以自由移动
the atoms can jiggle freely and move randomly,
但当你再一次把它冷却下来
but when you cool them back down,
这些原子便自发的重新排列起来
the atoms reorganize themselves,
重新变成晶体结构
reestablishing the crystal.
但是如果你可以很快地融化这些金属
But what if you could cool a molten metal so fast
快到原子们找不到它们应在的位置
that the atoms couldn’t find their places again,
那么这时 金属虽然变成了固体
so that the material was solid,
但是却拥有像液体一样混乱的非晶体结构
but with the chaotic, amorphous internal structure of a liquid?
这便是金属玻璃
That’s metallic glass.
这种结构优点还有:它没有晶粒边界
This structure has the added benefit of lacking the grain boundaries
大多数金属有晶粒边界
that most metals have.
晶粒边界是大多数金属最容易被刮破的脆弱的地方
Those are weak spots where the material is more susceptible to scratches
这些地方也容易被腐蚀
or corrosion.
【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
The first metallic glass was made in 1960 from gold and silicon.
这并不容易
It wasn’t easy to make.
因为金属原子结晶极为迅速
Because metal atoms crystallize so rapidly,
所以科学家们必须极快地把合金冷却
scientists had to cool the alloy down incredibly fast,
大概是以一百万开氏度每秒
a million degrees Kelvin per second,
他们把微粒射向冷铜片
by shooting tiny droplets at cold copper plates,
或者极薄的旋转带在那时
or spinning ultrathin ribbons.
金属玻璃只能有几十或几百微米厚
At that time, metallic glasses could only be tens or hundreds of microns thick,
这在应用中非常不切实际
which was too thin for most practical applications.
但是在那时以后 科学家们便发现
But since then, scientists have figured out
如果你将几种可以任意混合的金属混合在一起
that if you blend several metals that mix with each other freely,
它们便很难在一起结晶
but can’t easily crystallize together,
这往往归因于它们的原子大小不同
usually because they have very different atomic sizes,
它们的混合体结晶就慢了很多
the mixture crystallizes much more slowly.
这也就意味着你不需要那么快降温
That means you don’t have to cool it down as fast,
所以最后得到的材料变得厚了很多
so the material can be thicker,
可以达到几厘米厚
centimeters instead of micrometers.
这种材料被叫做块状金属玻璃
These materials are called bulk metallic glasses, or BMGs.
或BMGs现在我们有几百种不同的BMG
Now there are hundreds of different BMGs,
但是我们为什么不用他们做桥
so why aren’t all of our bridges and cars made out of them?
做车呢?已知的玻璃金属都是用昂贵材料做的
Many of the BMGs currently available are made from expensive metals,
比如钯和锆
like palladium and zirconium,
并且用的都是极纯净的金属
and they have to be really pure
因为任何杂质都会加速结晶
because any impurities can cause crystallization.
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
So a BMG skyscraper or space shuttle would be astronomically expensive.
尽管它们坚硬
And despite their strength,
可它们的韧性还不足以做承重类的应用
they’re not yet tough enough for load-bearing applications.
当压力很大的时候 它们容易毫无预兆地折断
When the stresses get high, they can fracture without warning,
这对于造桥可并不理想
which isn’t ideal for, say, a bridge.
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
But when engineers figure out how to make BMGs from cheaper metals,
同时也想出怎么能让它们的韧性变强
and how to make them even tougher,
那么这些材料
for these super materials,
便把人类的极限推到了天界的尽头
the sky’s the limit.

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