Y. Prawoto
材料科学技术（英）
In industrial application, unintentional manufacturing line troubles often consequence in heating raw materials excessively, in terms of either time or temperature. One of the effects of such occurrence is a product with a variation of prior austenite grain size, even if after the heat treatment the end result is the same, martensite. The variation of the prior austenite grain size is believed to vary the end results of the martensite. This undesirable variation includes the variation of fatigue resistance, impact strength, yield strength, hardness, etc. This research studies the effect of the prior austenite grain size on the morphology of the martensite microstructure. The results show that within the typical industrial application of temperature and holding time set up, as holding time or the temperature increases, the prior austenite average diameter increases. The block and packet sizes in the martensite also increase. The variation of mechanical property dependence on the grain size is indeed due to the different characteristics reflected in the martensite morphology. With
respect to the same area, smaller grain has more blocks and packets, which agrees with higher dislocation density verified with transmission electron microscopic evaluation.
关键词:
Heat treating
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null
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冯志海
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樊桢
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孔清
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熊翔
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黄伯云
新型炭材料
doi:10.1016/S1872-5805(14)60142-6
以高导热沥青基炭纤维布为增强体，中间相沥青为黏结剂，采用热模压成型及液相浸渍裂解工艺增密，并经高温石墨化处理制备二维高导热炭/炭复合材料。利用X射线衍射仪和透射电子显微镜对经不同温度处理后的沥青基炭纤维及二维高导热炭/炭复合材料的结构和形貌变化进行表征，并考察石墨化处理温度对复合材料热导率的影响。结果表明，随着热处理温度的升高，纤维及复合材料内部石墨微晶尺寸增大、取向度变好，纤维与基体间界面结合紧密、裂纹减少，而基体碳层间裂纹则呈扩大趋势。此外，二维高导热炭/炭复合材料的热导率随热处理温度的升高而线性增加，经3000℃处理后，材料热导率高达443 W/m·K。
关键词:
热处理
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炭/炭复合材料
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结构
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热导率
