等离子喷涂“桩钉结构”YSZ激光改性热障涂层的组织与性能（英文）

本试验采用大气等离子喷涂(APS)在含有NiCoCrAlYTa粘结层的镍基高温合金基体表面沉积氧化钇部分稳定氧化锆(YSZ)热障涂层,然后采用Nd:YAG的脉冲激光对热障涂层表面进行选择性激光表面改性处理,最后对喷涂态和"桩钉结构"激光改性YSZ涂层的组织与性能进行分析研究。结果表明:选择性激光表面改性形成的单元体表面粗糙度明显降低,表面的孔隙基本消除,同时形成了垂直于表面的分割网状裂纹,激光改性的"桩钉结构"单元体中还包含有柱状晶和等轴晶组织。XRD分析发现,喷涂态与"桩钉结构"单元体中都包含有非平衡四方相T',然而经过激光改性后,喷涂态中的单斜相M消失,72°~76°范围中T'峰明显增大。结果还发现,"桩钉结构"激光表面改性后,喷涂态YSZ热障涂层的平均结合性能由7.3 MPa增大到13.3 MPa;"桩钉结构"YSZ涂层的隔热性能比喷涂态的隔热性能有所下降,这是由于激光表面改性导致陶瓷层组织结构改变所造成的。     

等离子喷涂和激光熔覆热障涂层隔热性能比较

采用多种方法制备不同类型的Al2O3-13％TiO2热障涂层,即等离子喷涂常规涂层、纳米结构涂层及激光熔覆纳米结构涂层．在分析三类涂层微观组织的基础上,对其隔热性能进行了比较．结果表明,即等离子喷涂常规陶瓷涂层呈典型的层状堆积特征,纳米结构涂层都为特殊的两相结构,其中部分熔化区由类似的残留纳米粒子组成,等离子喷涂纳米结构涂层的完全熔化区为片层状结构,而相应的激光熔覆涂层的完全熔化区则为细小等轴晶．在相同条件下,等离子喷涂纳米结构热障涂层具有最好的隔热性能,而激光熔覆纳米结构涂层的隔热性能要好于等离子喷涂常规涂层．     

等离子喷涂常规和纳米ZrO2-7％Y2O3热障涂层隔热性能

采用等离子喷涂工艺在TiAl合金表面制备常规和纳米ZrO2-7％Y2O3(质量分数)热障涂层,分析了两种涂层的组织结构,并对其隔热性能进行了比较.结果表明,等离子喷涂常规热障涂层呈典型的层状堆积特征,而纳米涂层为特殊的两相结构.相对于常规涂层,纳米涂层有较好的隔热性能;在1100℃时,等离子喷涂常规及纳米涂层的隔热温度分别为83、127℃.     

激光表面改性对熔盐环境下热障涂层相稳定性和微观结构的影响

目的改善Y_2O_3部分稳定ZrO_2(YSZ)热障涂层的抗熔盐腐蚀性能。方法采用脉冲Nd:YAG激光系统对大气等离子喷涂YSZ热障涂层进行激光表面改性,优化激光参数,将喷涂态以及激光改性涂层在700℃和1000℃的V_2O_5熔盐下进行4 h热腐蚀实验。采用XRD、SEM和EDS表征腐蚀前后喷涂态和激光改性涂层的物相成分、微观结构和化学成分,通过计算热腐蚀后涂层表面的单斜(m)ZrO_2含量,分析激光改性对涂层相稳定性的影响。结果涂层表面的激光改性层呈现致密柱状晶结构并有一些贯穿的垂直裂纹。与原始涂层一样,改性层呈现亚稳态(t′)四方相。改性涂层在700℃腐蚀4h后,腐蚀产物为ZrV_2O_7、YVO_4和少量m-ZrO_2;在1000℃腐蚀4h后,腐蚀产物为m-ZrO_2和YVO_4。对未改性的YSZ涂层进行相同条件下的熔盐热腐蚀,其腐蚀产物种类与改性涂层相同,但是m-ZrO_2含量更高,表明更多的t'相受熔盐腐蚀而分解。结论激光改性可提高YSZ涂层中t'相的稳定性,使得涂层具有更好的抗熔盐腐蚀性能。然而,熔盐易沿垂直裂纹在改性层中渗入,不利于涂层的长期稳定性。     

冷喷涂Cu402F涂层激光重熔表面改性后摩擦学行为

目的研究激光重熔后冷喷涂Cu402F涂层在腐蚀介质中的摩擦学行为。方法采用冷喷涂技术在镍铝青铜9442合金上制备了厚度约为882.11μm的Cu402F涂层,并使用激光重熔技术对冷喷涂涂层进行表面改性。使用OM、SEM观察涂层截面与表面的微观形貌;使用XRD、X射线残余应力测试仪、多功能表面性能测试仪、多频直线往复磨蚀实验机,重点表征测试了涂层的组织、表面残余应力、摩擦学性能与磨蚀行为。结果激光重熔后的涂层分为表面重熔层、多孔的重熔过渡层以及冷喷涂遗传层。激光重熔前后,涂层的物相、残余应力均未发生较大变化。在20、50、100 N条件下,激光重熔态涂层的平均摩擦系数呈递增趋势,磨损率分别为1.01×10~(-2)、1.17×10~(-2)、1.34×10~(-2) mm~3/(N·m);由磨蚀实验可知,磨蚀是涂层表面产生钝化膜与钝化膜被破坏的此消彼长的过程,反映着摩擦与腐蚀的协同作用,涂层在磨蚀过程中,开路电位与摩擦系数呈正相关,说明激光重熔态涂层表面钝化膜产生的速度快于钝化膜被坏的速度。结论激光重熔保留了冷喷涂技术制备的Cu402F涂层的优点,同时激光重熔涂层上产生钝化膜的速度更快,有利于提高涂层的耐磨蚀性能。     

激光重熔对等离子喷涂热障涂层冲蚀行为影响

研究了等离子喷涂和激光重熔ZrO<,2>-7%Y<,2>O<,3>热障涂层的微观结构,同时考察了两种涂层的抗冲蚀性能,并探讨了其冲蚀破坏机理.试验发现,等离子喷涂热障陶瓷涂层呈典型的层状堆积特征;经过激光重熔处理后,涂层表面形成了沿热流方向生长的柱状品重熔区;相对于等离子喷涂试样,激光重熔涂层有较好的抗冲蚀性能;不管等...     

激光合金化掺杂TiC对等离子喷涂8YSZ热障涂层热腐蚀行为的影响*

传统的等离子喷涂热障涂层在高温环境下服役易受熔融腐蚀盐渗透而过早剥落失效，研究激光合金化掺杂自愈合材料 TiC 对热障涂层热腐蚀行为的影响具有重要意义。采用大气等离子喷涂技术（Atmospheric plasma spray，APS）在 Inconel 718 镍基高温合金表面制备 NiCrAlY 粘结层，采用大气等离子喷涂技术在 NiCrAlY 粘结层上制备 8 wt.%氧化钇部分稳定的氧化锆（8 wt.% yttria partially stabilized zirconia，8YSZ）陶瓷层，构建典型双层结构热障涂层体系。采用 1 kW 光纤耦合激光器将自愈合材料 TiC 熔于 8YSZ 热障涂表层，并考察其在 900 ℃下 25%NaCl+75%Na₂SO₄混合熔盐中保温 4 h 的热腐蚀行为。结果表明，与等离子喷涂涂层相比，激光合金化改性热障涂层表面更加光滑，分布有网状裂纹，且结构致密。等离子喷涂涂层的热腐蚀产物主要是针状颗粒 Y₂(SO₄)₃ 和 m-ZrO₂，但仅有较少的热腐蚀盐渗透至激光合金化改性热障涂层内部，其热腐蚀产物为 Y₂(SO₄)₃ 和少量的 TiO₂。激光合金化改性热障涂层的抗热腐蚀性能较等离子喷涂态热障涂层提升 55.5%，一方面激光合金化改性层组织致密，可阻止热腐蚀盐渗透至涂层内部，另一方面，激光合金化改性热障涂层表面粗糙度更低，能减少与热腐蚀盐的接触面积。此外，自愈合材料 TiC 在高温下发生氧化反应引起体积膨胀，实现裂纹的部分自愈合效应，进一步阻止了热腐蚀反应的发生。采用激光表面改性技术将自愈合材料 TiC 引入热障涂层，激光合金化改性热障涂层不仅具有光滑的表面形貌，还具有致密的微观组织结构；同时自愈合材料 TiC 在高温环境下的裂纹自愈合效应有助于抑制热腐蚀盐的渗透， 最终提高热障涂层的抗热腐蚀性能。     

CeO_2-Y_2O_3-ZrO_2热障涂层的组织结构及隔热性能

为获得孔隙率高、隔热性能好的热障涂层CeO2-Y2O3-ZrO2(CYSZ),采用低温超音速火焰喷涂(LT-HVOF)和大气等离子喷涂(APS)工艺在K4169镍基高温合金表面分别沉积NiCoCrAlYTa粘结层和CeO2、Y2O3共同稳定的ZrO2空心粉CYSZ陶瓷层。通过扫描电子显微镜(SEM)和X射线衍射仪(XRD)对不同喷涂电流(500,600和700A)制备的CYSZ热障涂层和采用传统Y2O3稳定的ZrO2团聚粉7YSZ为陶瓷面层的热障涂层的组织结构进行观察分析,并测定其隔热性能。结果表明:与传统的7YSZ类似,CYSZ涂层主要组成相为四方t相,涂层呈典型层状结构,但相对于7YSZ,空心粉CYSZ涂层存在更多孔隙和微裂纹;在1 150℃时,随着喷涂电流的增大,隔热性能呈降低趋势,CYSZ涂层隔热性能比传统7YSZ涂层隔热性能好。     

激光等离子复合热源喷涂工艺沉积机理研究

目的提高涂层的结合强度和改善微观组织结构。方法选取WC-10Co4Cr喷涂材料,分别通过激光等离子复合热源喷涂工艺以及等离子喷涂工艺制备涂层,对涂层组织与基本性能进行检测,对两种不同喷涂工艺的沉积机理作对比分析研究。研究复合热源喷涂涂层微观组织结构以及涂层与基体间结合方式较等离子喷涂涂层的变化。利用高速摄像仪对激光等离子复合热源喷涂以及等离子喷涂的工艺过程进行跟踪监测和分析,研究复合热源沉积过程中,基体表面微熔池的形成及粉末粒子在不同沉积工艺过程中熔融状态的对比,分析等离子喷涂涂层和复合热源喷涂涂层的沉积机理。结果等离子喷涂WC-10Co4Cr涂层以机械结合方式为主,涂层结合强度为39.5 MPa,孔隙率为1.7%,而激光等离子复合热源喷涂WC-10Co4Cr涂层实现了冶金结合,其结合强度提升到91 MPa,孔隙率降低到0.86%。结论激光等离子复合热源喷涂工艺可以有效提升涂层的结合力,改善涂层组织致密性,更有利于涂层的耐磨耐腐蚀性能。     

NiAl/NiCoCrAlY/8YSZ复合喷涂层的微观结构与性能研究

目的提高金属/陶瓷隔热涂层体系在海洋环境下的耐腐蚀性能。方法利用冷喷涂方法制备NiAl复合打底层和Ni CoCrAlY粘结层,与等离子喷涂制备的8YSZ陶瓷层构成适用于海洋环境的多层结构耐蚀隔热涂层体系。利用FE-SEM分别观察喷涂态粘结层和陶瓷层的表面、横截面形貌,通过EDS分析涂层元素分布;利用XRD分析表征涂层的物相组成;借助万能材料试验机,采用拉伸法测试涂层结合强度;利用热循环试验和焰流冲刷试验测试涂层的耐高温性能。结果微观分析表明,冷喷涂制备的NiAl复合打底层和Ni CoCrAlY粘结层形貌致密,涂层材料未发生明显氧化,颗粒变形程度不一,粘结层与基体间的结合强度约为18.4 MPa,粘结层与8YSZ陶瓷层界面结合紧密。陶瓷层物相结构和成分稳定,涂层经12次热震循环和1000个周期的高温焰流冲击后,表面未出现开裂、起皮和脱落。结论采用冷喷涂法和等离子喷涂法联合制备的耐蚀隔热复合涂层体系具备良好的耐热性和耐腐蚀性。冷喷涂制备的金属涂层结构致密,孔隙率低,与陶瓷层结合良好,能够有效提高涂层体系在腐蚀性环境中的耐蚀性能。NiAl复合涂层可以缓解Ni CoCrAlY粘结层和铝合金基材间的热匹配问题,增强涂层的结合性能。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

THERMODYNAMICS STUDY ON THE DECOMPOSITION OF CHROMITE WITH KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

INFLUENCE OF HEAT TREATMENT ON DAMPING BEHAVIOUR OF THE MAGNESIUM WROUGHT ALLOY AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

An Easy Way to Quantify the Adhesion Energy of Nanostructured Cu/X(X=Cr,Ta,Mo,Nb,Zr) Multilayer Films Adherent to Polyimide Substrates

An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quantitatively estimate the interfacial energy of the nanostructured multilayer films(NMFs) adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be *5.0 J/m2 for Cu/Cr, *4.1 J/m2 for Cu/Ta,*2.8 J/m2 for Cu/Mo, *1.1 J/m2 for Cu/Nb, and *1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.     

High-Speed Friction Stir Welding of SiC_p/Al–Mg–Si–Cu Composite

A 17 vol% SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed) at a very high welding speed of 2000 mm/min for the first time. Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed, due to the significantly reduced peak temperature and duration at high temperature. Therefore, prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed, which was similar to that of the nugget zone. Furthermore, the ultimate tensile strength of the joint was as high as 369 MPa, which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa). This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency.     

A STUDY OF TEMPERATURE-DEPENDENT VALENCE BOND STRUCTURE OF TITANIUM

On the basis of energy and shape method for the determination of the valence bond (VB) structures of crystal, the valence bond structure of titanium is redetermined at room temperature and calculated in the whole temperature range of 0-1943K. The outer shell electronic distribution of Ti is e_c~(2.9907) · (s_c~(0.4980) d_c~(2.4927)) ef1.0093 in crystal. The temperature dependences of the VB structures of hcp and bcc phases are the same. The VB structures of hcp and bcc phases monotonically increase or decrease with the increase in temperature, but show discontinuous changes at the phase-transformation temperature 1155K.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。