In nanoindentation, the occurrence of cracks, pileup, sink-in, or film delamination adds additional complexity to the analysis of the load–displacement curves. Many techniques and analysis methods have been used to extract both qualitative and quantitative information from the indentation test both during and after the test. Much of this information is obtained indirectly or may even be overlooked by current testing methods (e.g., cracks that open only during the loading cycle of the test may go unnoticed from a typical residual indentation analysis). Here we report on the development of a miniature depth-sensing nanoindentation instrument and its integration into a high-resolution scanning electron microscope. Real-time observation of the nanoindentation test via scanning electron microscopy allows for visualization and detection of certain events such as crack initiation, pileup, or sink-in, and other material deformation phenomena. Initial results from aluminum 〈100〉 and a thin gold film (∼225 nm) are presented.

Hollow carbon spheres encapsulating magnetite nanocrystals were obtained in high-pressure argon at 600 °C followed by hydrolysis of Fe(NH3)2Cl2 in the hollow interiors at room temperature and heat treatment in argon at 450 °C for 2 h. The structure, morphology, and properties of the products were characterized by x-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, and vibrating sample magnetometry. The hollow carbon spheres have diameters of 1–10 μm and wall thicknesses of hundreds of nanometers; the wt% of magnetite nanocrystals in them is ∼13.2%. Equiaxed magnetite nanocrystals range in size from 15 to 90 nm, while acicular magnetite nanocrystals have diameters of ∼20 nm and lengths of 120–450 nm. The saturation magnetization value of the hollow carbon spheres encapsulating magnetite nanocrystals is 4.29 emu/g.

In this study, we synthesized Cu–Zr binary alloys reinforced with an ultrafine eutectic microstructure. The alloys consisted of alternating layers of a hard superlattice phase and a ductile Cu phase with a very fine interlamellar spacing of ∼60 nm. The superlattice phase enhanced the strength of the alloys while the laminated composite structure helped improve their plasticity, making their mechanical properties comparable to those of the earlier reported high strength alloys. This paper discusses the fundamental microstructural aspects that influence the mechanical properties of these alloys.

The effect of minor addition (MA) of metallic alloying elements in Cu–Ti-rich Cu–Ti–Zr–Ni–Si bulk metallic glasses (BMGs) has been investigated. MA of elements having a relatively small positive enthalpy of mixing (partial substitution of Zr with Nb) leads to enhancement of compressive plasticity (up to about 5% of fracture strain) when the addition leads to improvement in glass-forming ability (GFA). If the GFA is reduced (partial substitution of Ni with Ag or Co), the plasticity is also reduced. On the one hand, the MA of elements having a relatively large positive enthalpy of mixing (partial substitution of Zr with Y) can lead to the liquid-state phase separation in Cu–Ti–Zr–Ni–Si(–Sn) BMGs, although the addition can lead to drastic deterioration in GFA and plasticity. This concept would be considered to be effective even in design of other BMG systems with tailored properties.

The evolution of microstructure and its influence on the mechanical properties of high-strength ultrafine eutectic Fe–(Ti, Zr)–(B, Co) alloys has been studied. The addition of B or Co improves the room temperature compressive plasticity from 1% to ∼8.5% or ∼14%, respectively, due to the formation of a heterogeneous microstructure with distinctly different length scales, which can delay the propagation of shear bands and promotes the activation of multiple shear bands.

Al/Ni multilayer foils were sputter-deposited with an in-plane residual stress state that was altered midway through the thickness of the foils by changing the bilayer spacing. The difference in stress between the top and bottom halves of the foil caused these systems to curl when they were removed from their substrates. As predicted, the radius of curvature increased linearly as the difference in stress between the upper and lower halves decreased and as foil thickness increased, demonstrating the ability to fabricate layered foils with specific curvatures. Unexpectedly, however, the radii of curvature of all the free-standing foils decreased with time after removal from their substrates, suggesting that a time-dependent relaxation mechanism was operating. An explanation based on stress driven, time-dependent deformation is offered to explain the relaxation, and an elasticity-based curvature model is presented for comparison with the measured steady state curvatures.

Electromigration at 5 × 104 A/cm2 and 100 °C was conducted to grow composite Pb/Sn whiskers from SnPb solders, in which a Pb whisker grows first and then a whisker of Sn grows. In some cases, small Sn islands are embedded in Pb whiskers. The diameter of a composite whisker is <1 μm, which is much smaller than that of spontaneous Sn whisker growth on leadframes. The growth orientation of Pb whiskers was in the [110], [1¯11], and [112] directions. This investigation proposes that compressive stress generated by electromigration at the anode provides the force driving whisker growth. Therefore, accelerated tests of whisker growth at higher temperatures using electromigration are feasible.

We investigated structural and characteristic changes in thin HfO2 films (<10 nm) by varying their thicknesses and also examined their influence on the properties of Pt/SrBi2Ta2O9/HfO2/Si metal/ferroelectric/insulator/semiconductor (MFIS) structures. HfO2 films with different thicknesses were found to exhibit rather distinct characteristics and to profoundly affect the properties of the fabricated MFIS capacitor. We found that, when employing 3.2-nm-thick HfO2 as the buffer layer, the MFIS capacitor showed good memory performance at low operation voltage. However, this study demonstrated that some of the HfO2 limited its application in MFIS memory, even though it is the most promising alternative gate dielectric material.

Grain growth in 40-nm-thick Cu films encapsulated by over- and under-layers of SiO2, Al2O3, Si3N4, and MgO was investigated. The films were magnetron sputter deposited onto cooled SiO2/Si substrates in an ultrahigh vacuum purity environment. Ex situ annealing was performed at 400 and 800 °C in 1 atm reducing gas. Films deposited at −120 °C exhibited more extensive grain growth after annealing than films deposited at −40 °C. Films annealed at room temperature had grain sizes less than 35 nm. All films exhibited some void formation after annealing at 400 and 800 °C, but the films encapsulated in Al2O3 exhibited the lowest area fraction of voids. The mean grain sizes of the Al2O3-encapsulated films, as measured by the linear intercept method, were 86 and 134 nm after annealing at 400 and 800 °C, respectively.