【正文】 d the final mechanical properties of steel products．Now a steel of warranted position is delivered to the user. （鍛造、沖壓等），則其初始組織和機(jī)械性能將會(huì)改變。所供給的鋼應(yīng)具有國(guó)家標(biāo)準(zhǔn)規(guī)定的各種性能。 In the RSSU．Plain carbon steels are classified into three groups：A, B and C，depending on their application. 在RSSU中，普通碳鋼根據(jù)其用途分為A、B、C三類。此時(shí)/在這種情況下，鋼的成分對(duì)用戶來(lái)講是最重要的，因?yàn)樗?成分)決定了熱加工的條件，鋼制品的最終機(jī)械性能。這種情況下，供給用戶的鋼應(yīng)具有規(guī)定的成分和機(jī)械性能。硫、磷是鋼中有害的雜質(zhì)，應(yīng)盡可能減少其含量，它們會(huì)影響鋼的質(zhì)量。我們將簡(jiǎn)要介紹幾種非鐵合金及其主要特征。鋁礦石的產(chǎn)量很大（占地殼的8％），并且鋁是可以回收的。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(guò)活性氧和硝酸鹽分離鈦金屬的工藝。與Al、Mg一樣，鈦合金密度比鐵低。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。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。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。這是很好的固溶硬化的例子。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。鉛的高密度、高成形性和低熔點(diǎn)使其具有多種用途。然而，它們一般與氧反應(yīng)，高溫服役時(shí)需控制氣氛，或帶有保護(hù)層。recrystallizationaboveslowaboveAc3,notprocedureannealing.annealedtostructuralstructureferrite,+ This type of heat treatment is called normalizing and is an intermediate stage between the second group procedure (annealing) and the thirdgroup procedure (hardening). 這種類型的熱處理被稱為正火,且為第二組之間的中間階段過(guò)程(退火)和第三種過(guò)程(硬化)。aboveAc3,cooling.austenite+.rate,at隨著冷卻速率增加,轉(zhuǎn)換發(fā)生在更低的溫度。ismixturemoreIfisandsubstantialofdoestherenosolid(will(supersaturatedofInpleteheatheatingAc1,AC3thehypoeutectoid如果冷卻速度很高,和過(guò)冷度大幅的提高，滲碳體和鐵素體沒有發(fā)生,不會(huì)有固溶體的分解并且奧氏體(r 固溶體)將轉(zhuǎn)變成馬氏體(airon碳過(guò)飽和固溶體)。aabelowcoolingat31As the phenomenon of superplasticity moves from the laboratory into the industrial arena, as in the case of a number of engineering metals, the need for quality and process control during superplastic forming bees increasingly important. This calls for laboratory characterization of superplastic metals which can reflect their behavior in actual forming applications. Such requirements are not limited to determining tensile elongations under optimum superplastic conditions, but include detailed characterization of the constitutive relations for superplastic flow, since a reasonably accurate control of the pressurization cycle during forming is required. This