【正文】 tems and characteristic brittleness．鎂合金的密度比鋁合金的還低，因此，設(shè)計航空飛行器時大量的結(jié)構(gòu)件用鎂合金。鋁合金是面心立方結(jié)構(gòu)金屬，因此，有12個滑移系，使其延展性好。相反，鎂合金是密排六方結(jié)構(gòu)，僅有3個滑移系，易脆斷（具有脆性）。Titanium alloys have bee widely used since World WarⅡ．Before that time，a practical method of separating titanium metal from reactive oxides and nitrites was not available. Once formed, titanium’s reactivity works to its advantage．A thin tenacious oxide coating forms on its surface, giving excellent resistance to corrosion. This “passivation” will be discussed in detail later. Titanium alloys，like Al and Mg，are of lower density than ion. Although more dense than Al or Mg，titanium alloys have a distinct advantage of retaining strength at moderate service temperatures, leading to numerous aerospace design applications. Titanium shares the hcp structure with magnesium leading to characteristically low ductility. However，a high temperature bcc structure can be stabilized at room temperature by certain alloy additions such as vanadium.二戰(zhàn)以后鈦合金被廣泛應(yīng)用，在此之前，還沒有通過活性氧和硝酸鹽分離鈦金屬的工藝。一旦形成鈦合金，鈦的活性顯現(xiàn)出其優(yōu)點。其表面形成致密的氧化膜，使其就有優(yōu)良的抗腐蝕性?！扳g化性”將在后面詳細(xì)討論。與Al、Mg一樣，鈦合金密度比鐵低。盡管密度要比Al、Mg高，鈦合金的顯著特點之一是在中等服役溫度下能保持其強度，因此航天中應(yīng)用多。與鎂合金一樣，鈦合金也是Hcp晶格結(jié)構(gòu)，延展性低。然而，通過添加釩等合金，其高溫下bcc晶格結(jié)構(gòu)可以在室溫下保存。Copper alloys possess a number of superior properties. Their excellent electrical conductivity makes copper alloys the leading material for electrical wiring. Their excellent thermal conductivity leads to applications for radiators and heat exchangers. Superior corrosion resistance is exhibited in marine and other corrosion environments. 銅合金也擁有許多優(yōu)良的性能。優(yōu)良的電導(dǎo)率使銅合金成為電線的首選材料。優(yōu)良的熱導(dǎo)率使其應(yīng)用于散熱器和熱交換器上。超級抗腐蝕性使其用于船舶及其它腐蝕性環(huán)境中。The fcc structure contributes to their generally high ductility and formability. Their coloration is frequently used for architectural appearance. Widespread uses of copper alloy through history have led to a somewhat confusing collection of descriptive terms．The mechanical properties of these alloys rival the steels in their variability.Fcc晶格結(jié)構(gòu)使其具有高延展性和成形性。其顏色經(jīng)常用于建筑裝飾中。銅合金的廣泛應(yīng)用使其描述詞語選擇時經(jīng)?；煜?。優(yōu)良的機械性能使其應(yīng)用上很具有競爭性。High purity copper is an exceptionally soft material. The addition of 2 wt％ beryllium followed by a heal treatment to produce CuBe precipitates is sufficient to push the tensile strength beyond l000 MPa．純銅非常軟。熱處理時添加2wt％的鈹元素，產(chǎn)生的CuBe沉淀相使其拉伸強度可超過1000MPaNickel alloys have much in mon with copper alloys．We have already used the CuNi system as the classic example of plete solid solubility. Monel is the name given to mercial alloys with NiCu ratios of roughly 2:1 by weight. These are good examples of solution hardening. Nickel is harder than copper, but Monel is harder than nickel. 鎳合金比銅合金更普通。Cu－Ni合金已是典型的完全固溶例子。比例接近2：1的Ni －Cu商業(yè)合金稱之為蒙乃爾合金。這是很好的固溶硬化的例子。Ni比銅硬，但是蒙乃爾合金比Ni硬。Nickel exhibits excellent corrosion resistance and high temperature strength. Zinc alloys are ideally suited for die castings due to their low melting point and lack of corrosion reaction with steel crucibles and dies. Automobile parts and hardware are typical structural applications. Zinc coatings on ferrous alloys are important means of corrosion protection. This method is termed as galvanization鎳有優(yōu)良的腐蝕性和高溫強度。由于熔點低不與鐵質(zhì)坩鍋和模具材料發(fā)生腐蝕反應(yīng)，鋅合金是模具鑄造的理想材料。其(鋅合金)應(yīng)用于典型的汽車結(jié)構(gòu)零件及硬度高的零件。鐵合金上鍍鋅層是重要的防腐蝕措施，該方法稱之為鍍鋅。Lead alloys are durable and versatile materials. The lead pipes installed by the Romans at the public baths in Bath, England, nearly 2000 years ago are still in use. Lead’s high density and deformability bined with a low melting point adds to its versatility．Lead alloys find use in battery grids (alloyed with calcium or antimony), solders (alloyed with tin), radiation shielding，and sound control structures. The toxicity of lead restricts design applications and the handling of its alloys.鉛合金是耐用的多功能材料。2000年前羅馬人安裝在英國公共浴室的鉛管至今仍然在用。鉛的高密度、高成形性和低熔點使其具有多種用途。鉛合金用于電池鉛版(與鈣、銻混合)、焊料（與錫混合）、