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研究了焊接CGHAZ的相变超塑性变形及其对疲劳寿命的作用。结果发现:(1)采用相同焊接循环与不同的拘束位移,所模拟的焊接CGHAZ中存在着相变超塑性现象。(2)该超塑性应变为1%时,其疲劳寿命要比无相变超塑性的提高19%。(3)在无相变超塑性CGHAZ中,(M-A)组元的形态基本上呈长条状;当相变超塑性应变增至1.0%时,(M-A)组元变化成长条状与块状的混合型形态。 相似文献
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本文借助于透射电镜和电子衍射分析手段,研究了15CrMoV钢在拘束多层焊条件下,各焊层近缝区粒状贝氏体精细结构与韧性的对应关系。研究结果表明:随着焊层数增大,(M—A)组织的精细结构发生本质性的变化,由高碳的孪晶马氏体向低碳的位错马氏体转化;铁素体基体的精细结构,由单纯的高密度位错特征逐渐转化到其上再弥散分布着极细的V_4C_3析出相。与此相对应,该近缝区随着焊层数增大韧性依次提高。 相似文献
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Fuzzy Multiple Attribute Decision Making for Evaluating Aggregate Risk in Green Manufacturing 总被引:2,自引:0,他引:2
Industrial risk and the diversification of risk types both increase with industrial development. Many uncertain factors and high risk are inherent in the implementation of new green manufacturing methods. Because of the shortage of successful examples and complete and certain knowledge, decision-making methods using probabilities to represent risk, which need many examples, cannot be used to evaluate risk in the implementation of green manufacturing projects. Therefore, a fuzzy multiple attribute decision-making (FMADM) method was developed with a three-level hierarchical decision-making model to evaluate the aggregate risk for green manufacturing projects. A case study shows that the hierarchical decision-making model of the aggregate risk and the FMADM method effectively reflect the characteristics of the risk in green manufacturing projects. 相似文献
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藉助于Gleble1500热模拟试验机,采用模拟焊接热循环拘束位移的方法,测定了HT80钢模拟CGHAZ的膨胀曲线和拘束应力曲线,研究了CGHAZ的相变超塑性现象,并试验获得了静拉伸强度与塑性.试验结果表明:(1)在模拟焊接CGHAZ中确是存在着相变超塑性,其变形量随着拘束位移的增大而增大;(2)相变超塑性具有使CGHAZ晶粒细化、降低强度和提高塑性的作用,这些都是以往难以实现的问题;(3)焊接过程的强拘束导致CGHAZ发生相变超塑性,不仅降低了CGHAZ的残余应力,而且改善了显微组织与力学性能 相似文献
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