热变形后的冷却方式对白口铸铁组织与性能的影响

对经４０％热度变形后不同冷却方式白口铸铁的组织与性能进行观察，并对其进行了分析，所得结果对白口铸铁的应用具有重要的指导意义。     

热变形量对白口铸铁组织与性能的影响

对经不同热变形量的白口铸铁的组织与性能进行观察、测试及分析，所得结果对白口铸铁的应用具有重要的指导意义     

低合金白口铸铁共晶碳化物团球化工艺的研究

低合金白口铸铁是一种耐磨性能优良的铸铁材料,但其组织中共晶碳化物呈连续网状分布,削弱了基体的连续性,导致铸铁脆性过大。我们探讨了复合变质处理和热变形处理对共晶碳化物团球化的影响,同时还研究了共晶碳化物团球化对低合金白口铸铁机械性能和耐磨性的影响,结果表明,共晶碳化物团球化有利于白口铸铁韧性和耐磨性的大幅度提高。     

稀土在白口铸铁中应用的现状及前景

本文综述了国内外稀土在白口铸铁领域研究和应用情况，稀土能有效地改善白口铸铁组织与性能，白口铸铁是稀土在铸铁中应用的重要领域之一，有广阔的应用前景。稀土最佳的加入量、处理工艺、稀土对白口铸铁作用机理方面，都进行了不少工作，但还有不少问题有待于投入更大的力量进行更深入的研究。     

锻造白口铸铁的强韧化机理

：借助扫描电镜、透射电镜观察和分析了白口铸铁的微观组织。揭示了白口铸铁锻造强韧化的机理，从而为提高白口铸铁的强韧性提供了理论依据     

稀土变质处理对中锰白口铸铁组织和性能的影响

本文研究了稀土变质处理对中锰白口铸铁的碳化物、残留奥氏体、基体组织、夹杂物以及性能影响,从而获得了中锰白口铸铁的最佳稀土变质量,为生产强韧中锰白口铸铁提供了必要的工艺参数。     

用稀土处理白口铸铁的试验研究

本文研究了混合稀土对白口铸铁组织和性能的影响。发现用稀土处理可以细化白口铸铁组织,使渗碳体呈细小、孤立状态分布,因而显著改善了白口铸铁的机械性能和切削加工性能。最佳混合稀土加入量约为0.3%。     

热处理对Cr20高铬铸铁组织和性能的影响

高铬白口铸铁在磨料磨损应用中具有极大的优越性。本文研究了不同热处理状态下高铬白口铸铁的性能、组织及二次硫化物的形成过程，并确定了组织与性能的相关性，对热处理工艺的选择进行了分析与讨论，为实际生产中热处理规程的制定提供了依据。     

高铬白口铸铁的结构研究

用扫描电镜、X—射线衍射分析仪及光学显微镜对5种亚共晶成份高铬白口铸铁的铸态结构进行了研究。结果表明,高铬白口铸铁中的碳化物组成及形态依赖于Cr/C值而变化,晶界处存在Cr,Si元素偏析。     

高碳高铬铸铁的组织及其磨蚀行为研究

设计了高铬白口铸铁的化学成分，研究了不同碳含量与热处理对其组织与性能的影响，结果表明，高碳高铬白口铸铁在ｐＨ＝３～７的弱酸性和中性介质中使用，其性能达到或超过硬镍１号水平，而且成本又比较低，具有广阔的应用前景。     

低合金白口铸铁的稀土铝氮综合变质机理

通过稀土铝氮综合变质处理使低合金白口铁中碳化物成为团块状,并使韧性显著提高。根据稀土、铝和氮三种变质元素分别及一同加入铁水后浇注成试样的物理冶金检测结果,讨论了各变质元素在熔体中的物化行为及这些行为对白口铸铁凝固的影响,尤其对碳化物结晶的影响。     

抗磨锰钛白口铸铁

研究了钛对抗磨锰钛白口铸铁显微组织和力学性能的影响，钛在显微组织中主要以TiC的形式存在，TiC的数量、尺寸和形态随钛含量的增加而改变，钛能细化奥氏体枝晶，促进渗碳体断网，降低材料硬度，提高冲击韧性和抗磨性，钛含量为0.28%的锰钛白口铸铁，能达到力学性能与抗磨性的最佳配合，正火处理可进一步提高材料性能。     

多元合金化新型低合金白口铸铁的组织与性能研究

设计了新型低合金白口铁的显微组织和化学成分，研究了稀土复合处理与热处理对其组织和性能的影响，试验结果表明，它具有良好的综合机械性能。此外，还地ＰＨ＝６的弱酸性砂浆冲蚀磨损机理进行了初步的探讨。     

白口铁热变形时碳化物破碎行为的研究

本文通过对不同变形量的白口铁中碳化物形貌的扫描电镜观察及定量金相研究，结合变形力学和热力学原理揭示了白口铁热变形过程中碳化物的破碎行为。所得结果对改善白口铁脆性扩大其应用具有重要的指导意义。     

Superplasticity in Rapidly Solidified White Cast Irons

Superplastic properties of three different composition white cast irons were investigated in the temperature range of 630 to 725 °C. Fine structures consisting of 1 to 2 μm ferrite grains were developed in these materials by consolidation of rapidly solidified powders at intermediate temperatures below the A₁ critical temperature. Tensile elongations of 1410 pct were found for a 3.0 pct C + 1.5 pct Cr white cast iron, 940 pct for a 3.0 pct C white cast iron, and 480 pct for a 2.4 pct C white cast iron when tested at 700 °C and at a strain rate of 1 pct per minute. The superplastic white cast irons exhibited a high strain rate sensitivity exponent,m, of 0.5 and activation energies for plastic flow were found to be nearly equal to the activation energy for grain boundary self-diffusion in iron. These observations are in agreement with the creep behavior of superplastic materials controlled by grain boundary diffusion. OSCAR A. RUANO, formerly with the Department of Materials Science and Engineering, Stanford University. LAWRENCE E. EISELSTEIN, formerly with the Department of Materials Science and Engineering, Stanford University.     

Modification of 27Cr cast iron with alloying yttrium for enhanced resistance to sliding wear in corrosive media

Yttrium has been found to be beneficial to the wear resistance of (Cr, Al)-containing alloys in corrosive environments. In this study, the performance of chill-cast 27Cr white iron alloyed with yttrium during sliding wear in different media, including tap water, dilute NaOH, and HNO₃ solutions, was investigated. Compared to Y-free 27Cr cast iron, the Y-containing cast iron showed improved wear resistance. The study demonstrated that chill-cast 27Cr white iron containing 1 wt pct yttrium performed the best and that too much yttrium, however, deteriorated the material. In order to understand the beneficial role that yttrium played, mechanical properties of Y-containing and Y-free cast irons and their passive films were investigated. The electron work function, corrosion, and anodic polarization behavior of the materials were also studied. It was clarified that the beneficial role of yttrium was attributable to improved passivation capability with enhanced passive film. For comparison, sandcast 27Cr white iron was also investigated.     

Effect of RE Elements on the Morphology of Carbides and the Impact Fatigue Properties of the Low Cr White Cast Iron

An apparatus of zone melting unidirectional solidification with a steep temperature gradient andan impact fatigue tester were used.The effect of RE elements on the morphology of carbides and the impactfatigue properties of the low Cr white cast iron were investigated.Experimental results showed that the modi-fying effect of RE elements was remarkable on the M3C carbides.With the addition of RE elements in thelow Cr iron,a lot of plate-like carbides were transformed into lath-like and rod-like ones.The higher thecontent of RE elements was,the more was the fraction of the lath-like and rod-like carbides.In the low Crwhite cast iron,the RE modifying agent can efficiently increase the impact fatigue resistance and decrease thecrack growth rate and delay the time of incipient cracking.With the increase of the content of RE elements inthe low Cr cast iron,the impact fatigue resistance increased greatly and the crack growth rate decreased rap-idly.