本文以30Cr Mn Si A结构钢为研究对象,利用低温等离子体渗氮及低温渗氮-低温氧化复合技术对其进行表面改性研究,重点研究了氧化时间对渗氮30Cr Mn Si A钢表面组织结构和性能的影响。采用扫描电子显微镜、X射线衍射仪分析渗氮层及渗氮-...
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本文以30Cr Mn Si A结构钢为研究对象,利用低温等离子体渗氮及低温渗氮-低温氧化复合技术对其进行表面改性研究,重点研究了氧化时间对渗氮30Cr Mn Si A钢表面组织结构和性能的影响。采用扫描电子显微镜、X射线衍射仪分析渗氮层及渗氮-氧化复合改性层的表面形貌、截面组织和相结构;利用维氏硬度计、摩擦磨损试验机和电化学工作站对渗氮层及复合改性层的硬度、耐磨性和耐蚀性进行评价。结果表明,渗氮层表面主要由ε-Fe_(23)N、γ'-Fe_(4)N和α_N相组成,经不同时间的氧化处理后,渗氮层表面生成Fe_(3)O_(4)相和Fe_(2)O_(3)相;随着氧化时间的延长,氧化物的含量增大,表面硬度增大,最大可达1012 HV_(0.05),改性层的有效硬化层厚度约为200μm;在防腐耐磨方面,渗氮层和渗氮-氧化复合改性层的耐磨性和耐蚀性均显著提高,且短时间氧化的复合改性层具有更好的耐磨性和耐蚀性。
Mg-5Li-3Al-2Zn-xCe（x=0-2.5;mass fraction,%） alloys were prepared by casting,and heat treatments of homogenization at 300 °C and solid solution at 370 °C were carried *** microstructure and tensile properti...
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Mg-5Li-3Al-2Zn-xCe（x=0-2.5;mass fraction,%） alloys were prepared by casting,and heat treatments of homogenization at 300 °C and solid solution at 370 °C were carried *** microstructure and tensile properties of as-cast alloys and their evolutions after solid solution were *** results show that with the increase of Ce content,Al2Ce/Al3Ce precipitates are formed and the alloys mainly consist of α-Mg,Al2Ce,Al3Ce and AlLi phases,and the amount of AlLi and Al-Ce intermetallics decreases after solid *** content and morphology of the second phases have important effects on the mechanical properties of the alloys;the alloy with 1.0%Ce content exhibits excellent tensile *** tensile strength and elongation of Mg-5Li-3Al-2Zn-0.5Ce alloy is remarkably improved by the solution strengthening effect because of the addition of Ce.
B 4 C p /Mg-8Li-1Zn and B 4 C p /Mg-8Li-1Al-1Y composites were prepared with hot-extrusion solid-state composite processing. The microstructures and mechanical properties of the composites were studied. With the optim...
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B 4 C p /Mg-8Li-1Zn and B 4 C p /Mg-8Li-1Al-1Y composites were prepared with hot-extrusion solid-state composite processing. The microstructures and mechanical properties of the composites were studied. With the optimized parameters, the deformation effects and the migration of α phase are improved, and the amount and size of foil gaps are decreased. The bonding force between foils is improved, and the oxidation of foils is lowered. The results of tensile test show that the strengths of the B 4 C p /Mg-8Li-1Zn and B 4 C p /Mg-8Li-1Al-1Y composites are increased obviously after hot-extrusion solid-state composite processing （238 MPa and 257.23 MPa, respectively）. The specific strength of B 4 C p /Mg-8Li-1Al-1Y composite is the highest （169.23×10 3 cm）.
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