A Ni-based alloy Ni-(12~18) Cr, (10~14) Co, (2~6) W, (2~6) Mo, (2~6) Ti, (2~6) Al was prepared via hot isostatic pressing by 150 MPa at 1150 oC with its argon gas atomization powders as raw material. Then its oxidation behavior in air at 950 oC was studied by intermittent weighing method in terms of the oxidation kinetics, phase composition, microstructure and elemental distribution of oxide scale and characteristics of oxygen-affected zone etc. The results show that the oxidation resistance of the as-HIPed superalloy at 950 oC has reached the full oxidation resistance grade in accord with the national standards. Both the oxidation kinetics curve and the depth variation curve of oxygen-affected zone follow a parabolic law. In the early stage of oxidation, Ti and Al atoms in the matrix diffuse rapidly along the prior particle boundaries (PPB) towards the alloy surface and form a continuous mixed oxide layer of Cr2O3, TiO2 and Al2O3. However, oxygen atoms diffuse inward along the PPB and undergoes in-situ oxidation reaction with secondary phases to form granular internal oxide Al2O3. After 24 hours oxidation, the surface oxide scale consists of the outmost layer of mixed oxides TiO2 and Al2O3, and the inner layer of Cr2O3 oxide. The continuous internal oxides TiO2 and Al2O3 appear in Cr-depleted zone. In the later stage of oxidation (> 100 h), the outmost TiO2 oxide layer peels off from the alloy surface, and the internal oxides TiO2 and Al2O3 distributed in Cr-depleted zone in a continuous root-like manner. Finally, the high temperature oxidation mechanism and formation process of internal oxides in as-HIPed nickel-based superalloy was also discussed.

研究了热等静压态镍基高温合金的高温氧化动力学、氧影响区的特征、相组成、微观形貌和元素分布，总结了高温氧化特征和内氧化物的生成过程。结果表明，这种热等静压态高温合金在950 ℃的氧化属于完全抗氧化级别，其氧化动力学曲线和氧影响区深度的变化曲线都符合抛物线变化规律。在氧化初期，合金基体中的Ti、Al离子沿原始颗粒边界(PPB)向表面快速扩散并生成连续的Cr2O3、TiO2和Al2O3混合氧化层，而氧原子沿PPB向内扩散与第二相发生原位氧化反应生成颗粒状内氧化物Al2O3。氧化24h后合金表面的氧化层由最外部的TiO2、Al2O3混合氧化层和底部的Cr2O3氧化层组成，在贫铬区出现连续的内氧化物TiO2和Al2O3。在氧化后期(氧化时间超过100 h)合金表面氧化层中最外部的TiO2氧化层脱落，贫铬区中的内氧化物TiO2和Al2O3呈连续树根状分布。

The hot cracking characteristic of the welded Hastelloy X is studied through the metallographic investigation of the weld zone and the thermo-mechanical modeling of the pulsed Nd-YAG laser process in SYSWELD (TM). The location of liquation cracking is determined by the incorporation of precipitation and the microstructure evolution of Hastelloy X and the temperature and stress profiles of the weld regions. The results reveal that increasing the speed of welding, with the maintenance of the penetration depth of the weld, leads to a decrease in liquation cracking in the heat affected zone. Microstructural evaluation indicates that solidification cracks are initiated from liquation cracks in the base metal and are propagated intergranular along the grain boundaries of the weld metal. It is also shown that the healing of liquated grain boundaries through backfilling can have a significant role in the resistance to liquation cracking in the heat affected zone and that, in turn, can affect tendency for solidification cracking in the weld metal. The analysis of the simulation identifies for d epsilon/dT higher than 0.007 (10(-3)/degrees K), the hot cracking is initiated in the middle zone of weld pool vicinity, where the strain rate was maximum.

The microstructure, micro zone properties, fracture morphology, and mechanical properties of different areas for the resistance spot welding joint of SUS301L stainless steel are systematically characterized via microhardness tester, electronic tensile shear testing machine, SEM, and IBIS. The results indicate that the morphology of the fusion zone in the joint is elliptical and which can be differentiated into the base metal zone, heat affected zone, and nugget zone. The microstructure distribution from the edge of the fusion core to the core center is columnar structure and equiaxed structure in sequence. The main defects of the joint include sputters on the edge of the fusion core, shrinkage porosity in the fusion core, and micro cracks, and the sputtering phenomenon is closely related to the occurrence of shrinkage porosity. The size of the nugget diameter is a key indicator that affects the mechanical properties, and there is a positive correlation between the two. As the thickness of the double-layer plate increases, the maximum tensile and shear force increment caused by the increment of the unit nugget diameter also significantly increases. The hardness and strength of the heat affected zone are lower than those of the base metal zone and the fusion zone, which leads to the formation of a softening zone at the corona bond. Due to the lower strength of this zone, the tensile shear force it can bear is relatively small, making it the starting area for tensile shear cracking. The forms of tensile shear fracture may be differentiated into passing through-core fracture and along-core fracture, the nugget diameter will affect the fracture mode of the joint.

介绍了弥散强化铜电阻焊电板材料的研究与发展过程, 并对采用内氧化法和机械合金化方法制备氧化铝铜电极的制备工艺以及有关使用性能作了简要叙述。

The microstructure and crystallographic structure characteristics of as cold-rolled strip and foil with different thicknesses of GH3536 alloy after annealing was investigated by optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray diffractometer (XRD) to get an insight into the recrystallization and grain growth behavior. The results show that the cold rolled strip and foil of GH3536 alloy show a microstructure composed of elongated grains along the rolling directions, and its main phase was γ. The grain growth equations of the strip and foil with thicknesses of 200,100 and 50 μm annealed at 1050~1150℃ for 10~60 min were established respectively, and the relevant activation energies were acquired as follows: Q200 μm=800.34 kJ/mol, Q100 μm=609.50 kJ/mol and Q50 μm=314.79 kJ/mol. The activation energy of the thinner strip and foil was smaller, and the grain growth was more prone to occur. The main factors affecting the grain growth were related to deformation degree and precipitated particles.

First-principles calculations were performed to determine the Fe on Fe (001) evaporation field and to characterize the surface diffusion of Fe and Cu on Fe (001) and on a step structure under an applied electric field. The evaporation field of Fe on Fe (001) was calculated by the nudged elastic band (NEB) method, using the combination of the effective screening medium and constant electrode potential methods to obtain a condition of constant electric field. The calculated evaporation field of Fe on Fe (001) was 32.4 V/nm, which agrees well with the experimental value. In the surface diffusion of Fe and Cu on Fe (001) and on a step structure, the activation barrier energies were determined by the NEB method with constant applied electric field. It was found that Cu diffuse more easily on the Fe (001) and step structure than Fe under an applied electric field. The activation barrier energy of surface diffusion in the saddle point configuration is small when the distance between Cu and Fe on the surface is larger, and the activation barrier energy becomes smaller when passing through a path far away from the surface due to the effect of the electric field.

The mechanical performance of electroplated Cu plays a crucial role in next-generation Cu-to-Cu direct bonding for the three-dimension integrated circuit (3D IC). This work reports direct-current electroplated (111)-preferred and nanotwin-doped nanocrystalline Cu, of which strength is at the forefront performance compared with all reported electroplated Cu materials. Tension and compression tests are performed to present the ultrahigh ultimate strength of 977 MPa and 1158 MPa, respectively. The microstructure of nanoscale Cu grains with an average grain size around 61 nm greatly contributes to the ultrahigh strength as described by the grain refinement effect. A gap between the obtained yield strength and the Hall–Petch relationship indicates the presence of extra strengthening mechanisms. X-ray diffraction and transmission electron microscopy analysis identify the highly (111) oriented texture and sporadic twins with optimum thicknesses, which can effectively impede intragranular dislocation movements, thus further advance the strength. Via filling capability and high throughput are also demonstrated in the patterned wafer plating. The combination of ultrahigh tensile/compressive strength, (111) preferred texture, superfilling capability and high throughput satisfies the critical requirement of Cu interconnects plating technology towards the industrial manufacturing in advanced 3D IC packaging application.