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  • 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.

    如果你將這些原料加熱到融化它們,

  • If you heat these materials up enough and melt them,

    原子便可自由晃動且任意移動。

  • the atoms can jiggle freely and move randomly,

    但當你把它們冷卻下來,

  • but when you cool them back down,

    原子便自己重新排列,

  • the atoms reorganize themselves,

    重組為晶體結構。

  • reestablishing the crystal.

    但如果你能將融化的金屬快速降溫,

  • But what if you could cool a molten metal so fast

    快到原子們找不到它們應在的位置,

  • that the atoms couldn't find their places again,

    此時,原料雖然是固體,

  • so that the material was solid,

    但卻擁有液體的 混亂、非結晶的內在結構,

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

    這便是「金屬玻璃」。

  • That's metallic glass.

    這種結構有另一個優點── 沒有晶粒邊界。

  • This structure has the added benefit of lacking the grain boundaries

    多數金屬有晶粒邊界。

  • that most metals have.

    晶粒邊界是原料較容易刮傷 或腐蝕的脆弱點。

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

    第一個金屬玻璃是在1960年 由金和矽做出來的。

  • or corrosion.

    這並不容易。

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

    因為金屬原子結晶極為迅速,

  • It wasn't easy to make.

    科學家必須把合金急速冷卻,

  • Because metal atoms crystallize so rapidly,

    一百萬開氏度每秒(降溫速度)

  • scientists had to cool the alloy down incredibly fast,

    藉著把微粒水珠射向冷銅片

  • a million degrees Kelvin per second,

    或做出超細的金屬絲。

  • by shooting tiny droplets at cold copper plates,

    那時,金屬玻璃只能做成 幾十或幾百微米厚 (µm),

  • or spinning ultrathin ribbons.

    因太薄而不切實用。

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

    但是自此,科學家便發現

  • which was too thin for most practical applications.

    如果將幾種容易混合的金屬互相摻雜,

  • But since then, scientists have figured out

    由於它們的原子大小極不相同, 致使不易結晶在一起,

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

    這混合物的結晶速度就變慢許多。

  • but can't easily crystallize together,

    這意味不需要那麼快速降溫,

  • usually because they have very different atomic sizes,

    所以材料可以比較厚,

  • the mixture crystallizes much more slowly.

    可達幾厘米厚 (cm) 而非微米 (µm)。

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

    這種材料稱為「大塊金屬玻璃」,或BMGs。

  • so the material can be thicker,

    現在已有幾百種不同的BMGs,

  • centimeters instead of micrometers.

    但為什麼不是所有的橋和車 都用這些材料製做呢?

  • These materials are called bulk metallic glasses, or BMGs.

    目前許多可用的BMGs 都是用昂貴金屬做的,

  • Now there are hundreds of different BMGs,

    比如鈀和鋯,

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

    它們必須很純,

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

    因為任何雜質都會導致結晶。

  • like palladium and zirconium,

    所以用 BMG 建摩天大樓或太空梭, 造價都是天文數字。

  • and they have to be really pure

    儘管它們堅硬,

  • because any impurities can cause crystallization.

    但還不夠堅硬到足以做承重類的應用。

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

    當壓力很大時, 它們會毫無預警地折斷,

  • And despite their strength,

    對於例如橋之類,並不理想。

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

    但是如果工程師想出 如何用更便宜的金屬製造 BMGs,

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

    以及如何讓它們更堅硬,

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

    那麼這些超級材料

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

    真是潛能無限啊!

  • and how to make them even tougher,

  • for these super materials,

  • the sky's the limit.

Steel and plastic.

鋼鐵和塑膠,

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B1 中級 中文 美國腔 TED-Ed 金屬 玻璃 堅硬 原子 結晶

【TED-Ed】什麼是金屬玻璃?- Ashwini Bharathula (【TED-Ed】What is metallic glass? - Ashwini Bharathula)

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    黃于珍 發佈於 2021 年 01 月 14 日
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