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感性,實際上工件在成型過程中遇到的應變速率有很大的差異,用應變速率的函數(shù)來測量拉伸伸長率是合理的。although there is a substantial increase in the applications for bending, the two most mon forms of bendingrepresent technologies that are sometimes quite outdated for today39。作為一個實際問題,這些合金分為基于碳在合金成分兩大類。隨著進一步的壓力,動態(tài)再結晶發(fā)生多次新的再結晶晶粒本身加工硬化儲存能量的臨界水平。在今天的鍛造行業(yè)的技能和經(jīng)驗豐富的forgeman判斷增強調(diào)制解調(diào)器技術的機器,產(chǎn)生無與倫比的力量和實用的金屬部件。沒有他們提供的鍛件和性能特點,汽車,飛機,卡車,農(nóng)具,土方機械,導彈,工業(yè)發(fā)動機和機器,和國防的實現(xiàn),因為我們知道他們會不會是可行的。 F和在腐蝕性,環(huán)境,自然可以想出。在微合金鋼中,這通常是由于碳化物和氮化物或碳氮。 現(xiàn)在公認的熱加工物理冶金的原則。這些事實說明為什么金屬是可靠的結構材料和不可超越的非金屬材料。今天,金屬并不總是通過加熱鍛造,這種工作可以由多種類型的能提供壓力或迅速精密擠壓力的重型機械來執(zhí)行。由于形成過程微觀結構的變化同時發(fā)生的復雜性,這給材料工程師們提出了一個嚴峻的挑戰(zhàn)。to a temperatureretainswithmartensitesoandoccurscooling, a steel is heated above AC3 and then cooled in air, this will be the first step to change it to a state farther from the structural equilibrium. 如果一個鋼加熱到AC3以上,然后在空氣中冷卻,這將是改變它遠離結構平衡狀態(tài)的第一步。ofthesubsequentThe refractory metals include molybdenum,niobium,tantalum,and tungsten.They are, even more than the superalloys, especially resistant to high temperatures. However, their general reactivity with oxygen requires the high temperature service to be in a controlled atmosphere or with protective coatings.難熔金屬包括鉬、鈮、鉭、鎢,它們不僅僅是超合金,還特別耐高溫。優(yōu)良的機械性能使其應用上很具有競爭性。相反,鎂合金是密排六方結構,僅有3個滑移系,易脆斷(具有脆性)。用戶也會對鋼材的原始機械性能感興趣,因為未焊接的部分的性能是原始性能。此時/在這種情況下,鋼的成分對用戶來講是最重要的,因為它(成分)決定了熱加工的條件,鋼制品的最終機械性能。鋁礦石的產(chǎn)量很大(占地殼的8%),并且鋁是可以回收的。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晶格結構使其具有高延展性和成形性。鉛的高密度、高成形性和低熔點使其具有多種用途。abovenotto+cooling.rate,mixtureandtherewillheatthea31As 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 provides a significant challenge to the materials engineer because of the plexity associated with microstructural changes occurring simultaneously during forming.超塑性的現(xiàn)象從實驗室轉移到工業(yè)領域,如在許多工程金屬中,這種需求在超塑性質量和過程控制成形變得越來越重要。35Forgings are monly found in machines and conveyances at critical points of shock or stressparticularly where reliability and human safety are affected, and yet the great variety of shapes, sizes and properties available in forgings has extended the list of current applications and potential future uses far beyond this point.鍛件通常是用在在機器和交通工具中發(fā)生沖擊和壓力尤其是在可靠性和人身安全受到影響的關鍵處,但在提供種類繁多的形狀,尺寸和性能的鍛件中,鍛件的可用性已經(jīng)擴展了現(xiàn)有的應用,并且在未來潛在的用途遠遠超出了現(xiàn)在。但是,由于材料的塑性越高,金屬在塑性變形這一點,說,在裂紋尖端,經(jīng)過強化,骨折的過程中,涉及到一個逮捕。因此,在熱處理的主要因素是溫度和時間,所以,任何熱處理過程可以在溫度時間(Tτ)坐標表示熱處理條件的特點是通過以下參數(shù):加熱溫度T最大,即為合金金屬加熱的最高溫度;在加熱溫度τH保溫時間;加熱速率νH和冷卻速率如果加熱(或冷卻)是在一個恒定的速率,溫度時間關系會以各自的角度傾斜的直線描述。這是通常所帶來的兩階段滾動γ+α一個地區(qū)或氣溫仍然較低,單相鐵素體。從規(guī)模的角度來看,例如,鍛件的范圍可能從微小的收銀部分每盎司加權分數(shù),以大規(guī)模的結構組件加權數(shù)噸。由于材料的使用效率變得更加必要,鍛件的能力,以最小的重量提供實力變得更有吸引力。鍛造許可證予以細化和控制,以提供更好的機械性能的金屬結構。為了能夠把這些原則運用到商業(yè)工作流程,我們需要回答兩個主要問題:(一)多久再結晶后變形傳遞到位。%的碳之間。所有關鍵部件和元件,其中一個高可靠性的要求,都是用金屬制作的,而不是玻璃,塑料或石頭。在文獻中存在多種方法用于確定米,其中一些將在下面評論。room