【正文】 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。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。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。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。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。recrystallizationslowAc3,procedureannealedstructuralferrite, 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程(退火)和第三種過程(硬化)。Ac3,austenite.atismoreissubstantialdoesno((supersaturatedInpleteheatingAC3hypoeutectoidabelowat The characterization of superplastic behavior broadly includes the characterization of plastic flow, internal cavitation and fracture behaviors. The processing variables needed for an overall characterization of superplastic behavior are introduced in this section. The parameter which is monly selected as a measure of superplastic formability is the tensile elongation at the optimum superplastic temperature and strain rate. However, since this is a highly strainrate sensitive property, and actual parts can experience significant variations in strain rate during forming, it is sensible to measure tensile elongation as a function of strain rate. While this is somewhat time consuming, an alternate possibility is to determine the strainrate sensitivity of the flow stress, m(m is defined as d(lg o) /d(lg€ )) which has been shown to correlate well with tensile elongation for different classes of materials. Measurements of flow stress and strainrate sensitivity of flow stress can be conducted in a single test and may be used to determine the optimum strain rate for superplastic forming(where m is a maximum). Several methods for determining m exist in the literature, some of which will be reviewed subsequently. 超塑性行為的性質(zhì)大致包括塑性流動(dòng)，內(nèi)部空化和斷裂行為的表征。在在超塑性成形中，這種“應(yīng)變硬化”被認(rèn)為是主要與晶粒生長(zhǎng)發(fā)生有關(guān)。在今天的鍛造行業(yè)中鍛造工人的技能和經(jīng)驗(yàn)豐富的判斷通過現(xiàn)代工藝的機(jī)器而得到增強(qiáng)，生產(chǎn)出無與倫比的力量和實(shí)用的金屬部件。所有非金屬離子和共價(jià)鍵。 以上的人類使用的金屬材料，重量90%鐵合金。的組合物的5重量%的總的非碳的加入將作為低合金高合金鋼之間的邊界。在變形過程本身，例如一個(gè)滾動(dòng)的傳遞，加工硬化發(fā)生，但回收和再結(jié)晶過程的動(dòng)態(tài)軟化平衡。最后，他們確定的熱作產(chǎn)品的結(jié)構(gòu)和性質(zhì)。本節(jié)簡(jiǎn)要介紹了鍛造業(yè)和其產(chǎn)品，他們?cè)谖覀兊纳罘绞街械闹匾饔?，突出自己的技術(shù)和經(jīng)濟(jì)意義。因?yàn)閹缀跛械慕饘倏梢詡卧?，鋁鋯廣泛的組合，機(jī)械和物理性能可滿足要求苛刻的太空時(shí)代的應(yīng)用程序。鍛件經(jīng)濟(jì)競(jìng)爭(zhēng)力與其他類型的相應(yīng)的材料生產(chǎn)的零部件。鍛件產(chǎn)品的過程中，如舊的古代，是為明天的新。今天的大部分機(jī)器和交通工具的經(jīng)營(yíng)能力在很大程度上依賴于偽造組件實(shí)現(xiàn)的屬性。但鍛造的真正含義，可以更清楚地認(rèn)識(shí)到考慮多種方式服務(wù)人類和鍛造件，提供設(shè)計(jì)，采購和使用它們的重要特征。今天，金屬并不總是鍛造加熱和工作可能由幾種類型的應(yīng)用影響或擠壓力迅速精密重型機(jī)械執(zhí)行。最近的注意力已經(jīng)通過保留在熱加工材料的子結(jié)構(gòu)在強(qiáng)度增加。結(jié)構(gòu)性變化的應(yīng)變與位錯(cuò)密度增加放置在一個(gè)臨界應(yīng)變（εc）奧氏體鋼，鎳和銅合金材料的結(jié)果，直到達(dá)到儲(chǔ)存的能量足夠高時(shí)會(huì)導(dǎo)致動(dòng)態(tài)再結(jié)晶。只有在性能如強(qiáng)度高、耐蝕性能提高的改進(jìn)