微量锆对导电铝合金耐热性的影响

含０．１２％Ｚｒ与不含锆的铝合金棒材，经５３０℃×１．５ｈ固溶处理和２５０℃×４８ｈ时效处理，再经７０％的冷拨加工成中Φ４．５ｍｍ的线材。试验结果表明：前者比后者的耐热性有明显提高。

微锆铝合金导线时效工艺研究

试验测定了含0.12％Zr的铝合金经不同时效处理，再经70％冷技加工成形后的强度、导电率、耐热性、蠕变裂纹扩展速率，结果表明，250℃×48h时效处理的强度、耐热性、导电率较好，蠕变裂纹扩展慢，经济性好。对时效工艺影响微锆铝合金性能的原理进行了探讨。

时效对锆-锶复合微合金化6013铝合金性能的影响

采用光学显微镜、扫描电子显微镜和透射电子显微镜等分析手段,研究了时效对Zr-Sr复合微合金化6013铝合金硬度、电导率和抗晶间腐蚀性的影响。结果表明,随着时效时间的延长,该铝合金电导率逐渐升高,硬度先升高后降低,在191℃时效4 h达到最大值159 HV0.1。与欠时效、过时效态相比,峰时效态具有更严重的晶间腐蚀倾向;自然时效态不发生晶间腐蚀,只发生轻微点蚀。

Effect of Different Laser Energy Nitriding on the Fretting Wear Performance of Zr Alloy

The zirconium(Zr)alloy fuel cladding is one of the key structural components of a nuclear reactor and the first and most important line of defense for accommodating fission products.During the operation of nuclear reactors,Zr alloy fuel cladding is subjected to extreme harsh environments,such as high temperature,high pressure and high flow rate for a long period of time.The wear and corrosion resistance of Zr alloys is important for the safe operation of nuclear reactors.Surface modification can effectively improve the corrosion and wear resistance of fuel cladding.Compared with coating technology,nitriding technology does not have problems for bonding between the coating and the substrate.Current research on surface nitriding of Zr alloys mainly focuses on plasma nitriding and ion implantation techniques.Research on laser nitriding of Zr alloy surfaces and their fretting wear characteristics is scarce.In this study,the surface of Zr alloy was treated with laser nitriding at different laser energies.The microstructure of Zr alloy treated with different laser energies and its fretting wear performance were studied.The results showed that after nitriding with different laser energies,the surface of the Zr alloy showed a typical molten state after melting,vaporizing and cooling under the thermal effect of the laser,and this state was more obvious with the increase of the laser energy.At the same time,doping of N atoms and formation of the ZrN phase led to different cooling rates in the molten zone that produced large tensile stresses after cooling.This led to cracks on the surface of Zr alloys after laser nitriding at different energies,and the crack density increased with increasing laser energy.This also led to an increase in the surface roughness of the Zr alloy with increasing laser energy after laser nitriding treatment.Due to the presence of water in the industrial nitrogen,nitrides were generated on the surface of the sample along with some oxides.When the laser energy was 100 mJ,there was no ZrN generation,and N existed mainly as a diffusion layer within the Zr alloy substrate.ZrN generated when the laser energy reached 200 mJ and above,which increased with the increase of laser energy.Due to the generation of ZrN phase and the presence of some oxides,the surface Vickers hardness of Zr alloys after laser nitriding treatment at different energies increased by 37.5%compared to Zr alloys.After laser nitriding treatment,the wear mechanism of Zr alloys changed.For the untreated Zr alloys,the wear mechanism was dominated by delamination and spalling wear,accompanied by oxidative and abrasive wear.The phenomenon of delamination and peeling decreased with the increase of laser energy.Wear mechanisms changed to predominantly abrasive wear with oxidative wear and delamination spalling.The wear volume of sample nitriding with laser energy 400 mJ was reduced by 46.5%compared with that of untreated Zr alloy.

锆对铸态锰黄铜组织与性能的影响

研究了微量元素锆对铸态锰黄铜的硬度、微观组织、耐腐蚀性能、摩擦性能以及力学性能的影响。结果表明,与未微合金化的锰黄铜相比,锆微合金化锰黄铜的组织更细,硬度更高,其均匀腐蚀速率降低了4.9%,电化学腐蚀速率降低了74.5%,摩擦系数降低了19.3%,抗拉强度和屈服强度分别提高了5.5%和24.2%。

Effect of dissolved oxygen on corrosion behavior of Zr-0.85Sn-0.16Nb-0.37Fe-0.18Cr alloy in 500℃ and 10.3 MPa super-heated steam

To better understand the role of dissolved oxygen(DO) in affecting corrosion behavior of zirconium alloys,the Zr-0.85 Sn-0.16 Nb-0.37 Fe-0.18 Cr(wt.%) alloy was corroded in super-heated steam at 500℃ and 10.3 MPa under 1×10-6 DO and deaeration conditions.The microstructure of the alloy and oxide films was investigated by SEM,TEM,EDS and EBSD.Results show that the corrosion is aggravated under 1×10-6 DO.Compared with the deaeration condition,the oxide film is looser,and has more micro-cracks and more uneven inner surface under DO condition.For the oxide film forming under deaeration condition,the selected area diffraction(SAED) spots of planes(002)m,■ and(101)t are strong,while those of the(001)m and■ are weak.However,for the oxide film forming under DO condition,the SAED spots of planes(111)m,(200)m and(101)t are strong,while those of the(100)m and(110)m are weak.The higher DO content in super-heated steam accelerates the growth of oxide films,thus decreasing the corrosion resistance of zirconium alloys.