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To achieve efficient connectivity of dissimilar γ'-strengthened superalloy, transient liquid-phase (TLP) diffusion bonding of 718Plus and Ni3Al-based superalloys is carried out using BNi-2 interlayer at a constant temperature of 1100 °C with holding times of 3, 15, 30, and 60 min. It is shown in the results that when the holding time is insufficient, isothermal solidification transforms into athermal solidification. Due to the enrichment of B and Cr elements in liquid phase, ternary eutectic consisting of γ, Ni3B, and CrB is formed at the joint center. Ternary eutectic with higher hardness (≈600 Hv) is poorly bonded to the matrix, which can easily become crack initiation location and significantly deteriorated the tensile properties. In addition, microhardness of the joint becomes more uniform and tensile strength gradually increases due to the reduction of eutectic with holding time increasing. Isothermal solidification completes and a joint without eutectic structure is formed at 1100 °C for 60 min. Diffusion of Al atoms leads to the formation of γ' with gradient size and tensile strength is comparable to that of base metal which is about 690.93 MPa. [ABSTRACT FROM AUTHOR]

Closed-cell aluminum alloy (A356) foams with different percentages of Al-Ti-B are prepared by melt foaming method, using Ca and TiH2 as thickening agent and foaming agent, respectively. SEM and Quasi-static compression tests are performed to investigate the effect of Al-Ti-B on the microstructure and compressive properties of aluminum alloy (A356) foams. The results show that foams with Al-Ti-B percentage of 0.3 wt.% possess good combinations of micro hardness, yield strength, plateau strength, densification strain and energy absorption capacity under the present conditions. The reasons are mainly due to the foams with Al-Ti-B percentage of 0.3 wt.% possess optimal eutectic Si morphology (with eutectic Si existing in the forms of particles or short fiber). [ABSTRACT FROM AUTHOR]

Dealloying, a famous ancient etching technique, was used to produce nanoporous metals decades ago. With the development of dealloying techniques and theories, various interesting dealloying products including nanoporous metals/alloys, metal oxides and composites, which exhibit excellent catalytic, optical and sensing performance, have been developed in recent years. As a result, the research on dealloying products is of great importance for developing new materials with superior physical and chemical properties. In this paper, typical dealloying products from Cu-based metallic glasses after dealloying in hydrofluoric acid and hydrochloric acid solutions are summarized. Several potential application fields of these dealloying products are discussed. A promising application of nanoporous Cu (NPC) and NPC-contained composites related to the energy storage field is introduced. It is expected that more promising dealloying products could be developed for practical energy storage applications. [ABSTRACT FROM AUTHOR]

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