Deformation-induced martensites in metastable austenite stainless steels affect their physical and chemical properties. Electrochemically induced annealing (EIA) is a recently discovered phenomenon. Although the reason why EIA treatment causes martensite to decrease or disappear is not clear, the effect of the martensite decrease or disappearance is supposed to be the same as that caused by heat-treatment annealing. The pitting resistance of the EIA-treated samples is compared with that of the untreated ones, through open-circuit potential, metallurgical microscope observation, and potentiodynamic scanning. The following results are obtained for the EIA-treated samples, after a 1.5-V anode charge in a 3.5 pct NaCl solution, as compared with the untreated samples: the deepest pit in the treated samples is far more shallow than the deepest pit in the untreated samples; there is far less pitting in the treated samples than in the untreated samples; and the largest pit in the treated samples is much smaller than the largest pit in the untreated samples. Initially, the open-circuit potential of the EIA-treated sample was 64 mV higher than that of the untreated one, but they reach close values after certain period of time. The pitting breakthrough potential, Eb, of the EIA-treated sample is about 0.2 V higher than that of the untreated one. Therefore, EIA is a method that has the potential to promote the pitting resistance of metastable austenite stainless steels.

本文研究了SiCw/Al复合材料(碳化硅晶须增强铝复合材料) 的尺寸稳定性, 结果表明: 这种材料的微屈服强度、微蠕变抗力均明显高于其基体铝合金, 其热膨胀系数明显低于基体铝合金, 这种材料具有优异的尺稳定性。

用电镀的方法制备出Ni-纳米TiO2复合电镀层,讨论了表面活性剂、阴极电流密度、搅拌速率等对复合镀层硬度的影响并分析了纳米TiO2的加入对复合镀层硬度、耐蚀性的影响情况。结果表明,与纯镍镀层相比,Ni-纳米TiO2复合电镀层的硬度可提高90～190 HV;添加阳离子表面活性剂分散纳米TiO2所得复合镀层硬度最高,说明阳离子表面活性剂有利于纳米TiO2-Ni复合电沉积。浸泡试验表明,在硝酸溶液中复合镀层的腐蚀速率高于纯镍镀层的腐蚀速率,但远低于未镀覆钢板的腐蚀速率;极化曲线表明,与纯镍镀层相比,复合镀层的自腐蚀电位没有显著提高。说明在复合镀层中添加纳米TiO2不能改善其耐蚀性。

In thermal barrier coatings (TBC), ceramics is covered on the metal matrix as coatings in order to raise its temperature endurance. Today most of the TBCs are of the double-layer-structure of Ni base heat-resistant alloy matrix + the bonding layer of MCrAlY alloy (M = Ni, Co, Ni + Co) + ZrO2. In this paper, the concept of interface conjunction factor (ICF) in the biphase interface of alloys is expanded to coatings. The ICFs of the interface between the ceramics and the bonding layers with various compositions, such as the electron density ρ, the electron density difference△ρ, and the number of atom state group which keeps the electron density continuous s are calculated. From the calculation results, the following estimations can be deduced. When Al content is less than 6 wt% it improves the mechanical properties of the coatings; when the content is 6 wt%—12wt% it will not worsen the properties; when the content is greater than 12 wt% it will have disadvantageous effect. The estimations accord well with the experiment results of the properties and the service time of the coatings. Therefore the concept of ICF has the same important meaning in coatings, and the valence electron structure of the interface can be a possible theoretical guide for the content optimization of TBCs.

The second phase in multi-phase alloys has connection with many important phenomena such as aging strengthening, dispersion strengthening, secondary hardening, crystal refinement. In this paper, the interface conjunction factors of the interface between MC(M=V, Nb, Ti) and austenite and martensite are calculate out. The relationship between these factors and the characteristics are analyzed. The reason for the second phases being fine and dispersing and their strengthening and toughening effect on the alloy is explained using the relationship. Based on the relationship, the valence electron structure of the interface between the second phase particles and the matrix can be optimized by changing the alloying elements, which make it possible to design the composition of alloys from the valence electron structure of the second phase particles.