喷射成形1.8C-1.6Al超高碳钢快速凝固组织研究

铸造1．8C-1．6Al超高碳钢(UHCS)由于冷速较低，晶粒粗大，珠光体片间距也较大，品界形成了粗大的碳化物网络，同时合金元素产生偏析，品内生成了大块的合金渗碳体，使得它在室温下为脆性，机加工性能极差。喷射成形1．8C—1．6Al超高碳钢则利用喷射成形工艺冷却速度大的特点细化了晶粒，减小了珠光体的片间距，提高了硬度与强度，同时降低了元素偏析程度。同时发现：在铸态1．8C-1．6Al超高碳钢中和在喷射成形1．8C-1．6Al超高碳钢中Al在晶内的分布情况正好相反，由反偏析转变为正偏析。     

Improvement of SiC_p Reinforced Cast AluminiumComposites by the ROC Method

ＩｍｐｒｏｖｅｍｅｎｔｏｆＳｉＣ＿ｐＲｅｉｎｆｏｒｃｅｄＣａｓｔＡｌｕｍｉｎｉｕｍＣｏｍｐｏｓｉｔｅｓｂｙｔｈｅＲＯＣＭｅｔｈｏｄＺｈｅｎｇＱｉｆｅｉ，ＸｉｅＳｈｕｉｓｈｅｎｇ，ＹｕａｎＧｕａｎｓｅｎ，ＳｈｉＬｉｋａｉ（郑弃非）（谢水生）（袁冠森）（...     

用稀土钇提高离子镀TiN膜层与基体结合力的研究

研究了不同含量稀土钇对离子镀ＴｉＮ膜与基体结合力的影响，结果表明，加入稀土钇后，大大提高ＴｉＮ膜与基体的结合力，并使膜层内ＴｉＮ相增加，此外，稀土钇能明显提高镀膜过程中钛料蒸发率，在相同镀膜内，能使ＴｉＮ膜层加厚。     

富钛BaO-TiO2(Ti/Ba=4～4.5)系微波介质陶瓷

采用固相反应法制备了富钛BaTi4+xO9+2x(x=0.0-0.50)微波介质陶瓷,探讨了TiO2含量以及烧结温度对物相组成和介电性能的影响.在1300～1350 ℃烧结BaTi4+xO9+2x陶瓷即可达到约98%的相对密度.当x≤0.28时,BaTi4+xO9+2x陶瓷为BaTi4O9单相.随TiO2含量的增加,BaTi4+xO9+2x陶瓷从BaTi4O9单相逐渐转变成以BaTi4O9为主相,同时出现TiO2和Ba2Ti9O20相,并且随烧结温度提高,TiO2含量较多的试样中出现更多的Ba2Ti9O20相.随TiO2含量的增加介电常数逐渐增大,而Qf值呈下降趋势.Qf值从x=0.0时的约40 000 GHz逐渐降低至x=0.50时的15 000 GHz.     

Resistance of Mo-bearing stainless steels and Mo-bearing stainless-steel coating to naphthenic acid corrosion and erosion-corrosion

Naphthenic acid corrosion (NAC) and erosion-corrosion (NAEC) behavior of Mo-bearing (0-7.0 wt.%) stainless steels have been investigated in laboratory to evaluate the essential role of Mo on their NAC and NAEC resistance. The NAC and NAEC resistance of a high-velocity-oxygen-fuel (HVOF) thermal sprayed Mo-bearing stainless-steel coating was also investigated in both laboratory and an oil refinery. It was found that increasing the Mo content remarkably enhanced the NAC and NAEC resistance of stainless steels. The Mo-rich areas or phases in the steels played an importance role in resisting the NAEC. The HVOF coating showed excellent NAC and NAEC resistance in laboratory tests. The 700-day field test in an oil refinery revealed that the coating can effectively prevent the carbon-steel substrate from erosion-corrosion during long-term exposure in oil-refining environment. The corresponding NAC and NAEC mechanisms of the stainless steels and the beneficial role of Mo were discussed by taking account of inherent susceptibility of metal elements to corrosion, possible effects of Mo on surface films, and Mo-induced change in microstructure and microhardness.     

Numerical simulation of gas metal arc welding temperature field

The infrared camera is used to investigate the temperature field of gas metal arc welding.The results show that the temperature distribution of weld pool and adjacent area appears cone shape.A new heat source model combined by Gaussian distribution heat source of the arc and conical distribution heat source of the droplet is set up based on the experimental results, and with the combined boundary conditions,the temperature field of gas metal arc welding is simulated using finite element method.According to the comparison between the results of experiment and simulation in temperature field shows that the new combined heat source model is more accurate and effective than the Gauss heat source model.     

Size and pressure effects on solid transition temperatures of ZrO2

Transition temperatures between tetragonal and monoclinic polymorphs of ZrO₂ nanoparticles, thin films and nanostructured materials are calculated by considering energetic contributions of surface (interface) energy and surface stress on total Gibbs free energy. The transition temperatures drop as the size of the nanocrystals decreases, which is consistent with available results.     

焊接工艺参数对奥氏体不锈钢焊接接头腐蚀行为的影响

通过草酸腐蚀和硫酸-硫酸铁腐蚀实验，研究了奥氏体不锈钢焊接接头腐蚀与焊接热输入的关系。结果表明，随着焊接线能量的增加，其焊接接头腐蚀越严重。随着焊接线能量的增大，腐蚀率增大且有加速趋势。     

棒材无模拉伸温度场及温度梯度

采用有限元法对棒材无模拉伸温度场进行了研究,利用有限元分析软件对变形区温度场进行了数值模拟,分析了温度场及温度梯度的影响因素及影响规律,确定了变形区温度梯度分布规律。拉伸件轴向温度梯度dT/dz与其轴向坐标z之间呈线性关系,这就使得轴向各断面的平均变形抗力分布均匀,从而保证拉伸过程稳定进行。     

骨髓成骨细胞在碱热处理的磷灰石涂层钛表面的分化增殖研究

为了研究骨髓基质细胞转化的成骨细胞在碱热处理的涂层磷灰石钛表面的分化增殖，将钛片经过碱热处理后，浸泡于与类似体液的环境进行表面磷灰石涂层。应用骨髓成骨细胞作为实验工具，观察体外细胞在处理的涂层钛片上的生长，碱性磷酸酶以及降钙素的分泌。在早期，有磷灰石涂层的钛片成骨细胞黏附高于对照组；在晚期，两组之间没有明显差异；成骨细胞分化的标志——碱性磷酸酶活性和降钙素的表达，磷灰石涂层组都明显高于对照组。研究表明：碱热处理的磷灰石涂层钛能够促进成骨细胞黏附，有利于细胞向成骨分化。