【摘要】 用高分辨电子显微镜(HREM)进行了Nb、Cr、Mo、Ni等微合金元素复合微合金化的实用超低碳含Cu钢中时效析出相的形貌观察及晶体结构鉴定,探索将HREM分析技术有效应用于工程材料微观结构研究的新途径。在300万倍以上的放大倍率下清晰观察到了尺寸仅有十个nm左右的细小弥散分布的时效析出颗粒以及其中的孪晶结构,还有大量在局部微区形成的过渡结构。尝试用单个颗粒HREM像上的晶格条纹间距鉴定了钢中除ε-Cu以外的另3类时效析出相的晶体结构。结果表明,时效期间钢中析出Cu、Nb、Cr、Mo、Ni的特殊碳化物(碳氮化物),与ε-Cu共同产生时效强化作用。提出了用HREM像对实用钢材中弥散分布的微细析出相进行晶体结构鉴定的实验方法。更多还原

【Abstract】 A high resolution electron microscope(HREM) was used for morphology observation and crystal structure identification of fine age-precipitates in a practical ultra-low carbon Cu-bearing steel complex-microalloyed with Nb,Cr,Mo and Ni.A new approach to effectively apply HREM for microstructure study of engineering materials was explored.Fine dispersed single age-precipitated particle of 10 nm with twin structure and transient structure formed in local micro-areas was observed on the HREM at magnification of 3 × 106.The crystal structure of three types of age-precipitates except ε-Cu was identified by lattice streaks on HREM images of the single particles.The results show that Cu,Nb,Cr,Mo and Ni carbide(carbonitride) particles are precipitated during aging and produce age-strengthening with ε-Cu together.The experimental method for identifying the crystal structure of fine dispersive particles using HREM images is proposed.更多还原