武汉理工大学研究生--材料科技英语-课文翻译(2)

现在还有更多类型的纺织品用于增强体。所有长的狭窄的2D纺织品（毡，织物，针织物，编织物）都以其纤维结构及其单位面积的重量[g / m2]来描述。纤维结构是指织物各组分的取向和重量。

By special manufacturing methods, it is possible to obtain a new category of 3D textile architecture called 3Dtextiles. These are infiltrated with a resin to obtain composite materials with reinforcing fibers in all threedirections.The resulting composite material can be processed as a solid 3D bulk material that is then machined toshape or processed directly into the final shape of

the desired produce. 3D textiles can be made as 3D weaves or 3Dbraids. 通过特殊的制造方法，可以获得新类别的3D纺织品架构称为3D纺织品。它们被树脂浸润，可以获得在三个方向具有增强纤维的复合材料。所得到的复合材料可以作为固体3D体材料加工，然后将其加工直接成型或加工成所需产品的最终形状。3D织物可制成3D织物或3D编织物。

Polymer

Polymers vary widely in their mechanical behavior depending on the degree of crystallinity, degree ofcrosslinking, and the values of Tg and Tm. Elastomers are the group of polymers that can easily undergo very large,reversible elongations at relatively low stresses. This requires that the polymer be completely amorphous with a lowglass transition temperature and low secondary forces so as to obtain high polymer chain mobility. Some degree ofcrosslinking is needed so that the deformation is rapidly and completely reversible. Most elastomers obtain the neededstrength via crosslinking and the incorporation of reinforcing inorganic fillers. Some elastomers undergo a smallamount of crystallization during elongation, especially at very high elongations, and this acts as an additional

strengthening mechanism. The Tm of the crystalline regions must be below the use temperature of the elastomer inorder that the crystals melt and deformation be reversible when the stress is removed.

聚合物的机械性能有很大的不同，这取决于结晶度、交联程度以及Tg和Tm的值。弹性体是聚合物的一类，它可以在相对低的应力下很容易地进行非常大的、可逆的延展。这要求聚合物具有完全的非晶态，具有低的玻璃化转变温度和弱的次价键，从而获得高分子链的流动性。并且需要一定程度的交联，使变形迅速且完全可逆。大多数弹性体通过交联和加入无机填料来获得所需的强度。一些弹性体特别具有非常高的伸长率的弹性体在延展时进行少量的结晶，这也是一个额外的增强机制。结晶区的Tm必须低于弹性体的使用温度，以便在应力消除时晶体熔化和变形是可逆的。

Fibers are polymers that have very high resistance to deformation—they undergo only low elongations and havevery high moduli and tensile strengths. A polymer must be very highly crystalline and contain polar chains with strongsecondary forces in order to be useful as a fiber. Mechanical stretching is used to impart very high crystallinity to afiber. The crystalline melting temperature of a fiber must be above 200℃ so that it will maintain its physical integrityduring the use temperatures encountered in cleaning and ironing. However, Tm should not be excessively high—nothigher than 300℃. The polymer should be soluble in solvents used for solution spinning of the fiber but not indry-cleaning solvents. The glass transition temperature should have an intermediate value; too high a Tg interfereswith the stretching operation as well as with ironing, while too low a Tgwould not allow crease retention in fabrics.

纤维是具有非常高的抗变形性的聚合物 - 它们受力伸长率很低并具有非常高的模量和拉伸强度。用作纤维的聚合物必须非常高度结晶，并且含有具有强次价键的极性链。机械延展赋予了纤维很高的结晶度。纤维的结晶熔融温度必须在200度以上，以便在使用温度下清洗和熨烫过程中保持其物理完整性。然而，Tm不应过高—不高于300℃。聚合物应溶于用于溶液纺丝的溶剂，但不溶于干洗溶剂。玻璃化转变温度应该有一个中间值；过高的Tg会影响

拉丝操作和熨烫，而过低的Tg则不能保证织物的防皱。

Stainless steels

The stainless steels are highly resistant to corrosion (rusting) in a variety of environments, especially the ambientatmosphere. Their predominant alloying element is chromium; a concentration of at least 11 wt% Cr is required.Martensitic stainless steels are capable of being heat treated in such a way that martensite is the primemicroconstituent. For austenitic stainless steels, the austenite phase field is extended to room temperature. Ferriticstainless steels are composes of the ferrite phase. Austenitic and ferritic stainless steels are hardened and strengthenedby cold work because they are not heat treatable. The austenitic stainless steels are the most corrosion resistantbecause of the high chromium contents and also the nickel additions; and they are produced in the largest quantities.Both martensitic and ferritic stainless steels are magnetic; the austenitic stainlesses are not.

不锈钢在各种环境中特别是环境大气中具有很高的耐腐蚀性（防锈性）。它们的主要合金元素是铬，铬的含量至少需要11wt%。马氏体不锈钢由于马氏体是主要的微观组织成分，因此可以进行热处理。对于奥氏体不锈钢，奥氏体相领域延伸至室温。铁素体不锈钢由铁素体相组成。奥氏体不锈钢和铁素体不锈钢由于不可热处理而被冷加工硬化和加强。奥氏体不锈钢由于铬含量高，镍添加量高，因此耐腐蚀性最强，生产量也最大。马氏体和铁素体不锈钢都是磁性的; 奥氏体不锈钢则不是。

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