Microstructures and mechanical properties of high-strength Fe-Mn-Al-C light-weight TRIPLEX steels
Microstructures and mechanical properties of high-strength Fe-Mn-Al-C light-weight TRIPLEX steels
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DOI：
10.1002/srin.200606440
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发表时间：
2006-09-01
影响因子：
2.2
通讯作者：
Bruex, Udo
中科院分区：
文献类型：
--
作者：
Frommeyer, Georg;Bruex, Udo
一般成分为Fe-xMn-yAl-zC的高强度TRIPLEX轻钢含有18-28%的锰，9-12%的铝和0.7-1.2%的C（质量%）。微观结构由奥氏体γ -Fe（Mn, Al， C）固溶体基体组成，基体中分散有不同体积分数的纳米级卡帕碳化物（Fe,Mn）(3) AlC1-x和α -Fe（Al, Mn）铁素体。计算得到相变(gamma fcc) -> (epsilon hcp)的吉布斯自由能为δ G(gamma ->epsilon) = 1757 J/mol，层错能为gamma (SF) = 110 mJ/m(2)。这表明奥氏体非常稳定，不会形成应变诱发的ε -马氏体。在塑性变形过程中，机械孪晶几乎被抑制。TRIPLEX钢具有6.5 ~ 7g /cm(3)的低密度和优异的机械性能，如700 ~ 1100mpa的高强度和高达60%以上的总伸长率。在10(3)s（-1）的高应变速率下获得的比能吸收约为0.43 J/mm(3)。透射电镜观察清楚地表明，变形拉伸试样中均质剪切带的形成伴随着位错滑动。这些钢的主要变形机制是剪切带诱导塑性- sip效应-由与奥氏体基体相一致的纳米级碳化物的均匀排列维持。有效的固溶硬化和叠加的弥散强化是高流动应力和抗拉强度的主要原因。
High-strength TRIPLEX light-weight steels of the generic composition Fe-xMn-yAl-zC contain 18-28% manganese, 9-12% aluminium, and 0.7-1.2% C (in mass %). The microstructure is composed of an austenitic gamma-Fe(Mn, Al, C) solid solution matrix possessing a fine dispersion of nano size kappa-carbides (Fe,Mn)(3) AlC1-x and alpha-Fe(Al, Mn) ferrite of varying volume fractions. The calculated Gibbs free energy of the phase transformation (gamma fcc) -> (epsilon hcp) amounts to Delta G(gamma ->epsilon) = 1757 J/mol and the stacking fault energy was determined to Gamma(SF) = 110 mJ/m(2). This indicates that the austenite is very stable and no strain induced epsilon-martensite will be formed. Mechanical twinning is almost inhibited during plastic deformation. The TRIPLEX steels exhibit low density of 6.5 to 7 g/cm(3) and superior mechanical properties, such as high strength of 700 to 1100 MPa and total elongations up to 60 % and more. The specific energy absorption achieved at high strain rates of 10(3)s(-1) is about 0.43 J/mm(3). TEM investigations revealed clearly that homogeneous shear band formation accompanied by dislocation glide occurred in deformed tensile samples. The dominant deformation mechanism of these steels is shear band induced plasticity -SIP effect- sustained by the uniform arrangement of nano size kappa-carbides coherent to the austenitic matrix. The high flow stresses and tensile strengths are caused by effective solid solution hardening and superimposed dispersion strengthening.