A series of material parameters are derived from atomistic simulations and implemented into a phase field（PF） model to simulate void evolution in body-centered cubic（bcc） iron subjected to different irradiation doses at different temperatures.The simulation results show good agreement with experimental observations — the porosity as a function of temperature varies in a bell-shaped manner and the void density monotonically decreases with increasing temperatures; both porosity and void density increase with increasing irradiation dose at the same temperature. Analysis reveals that the evolution of void number and size is determined by the interplay among the production, diffusion and recombination of vacancy and interstitial.
Materials that undergo a reversible change of crystal structure through martensitic transformation （MT） possess unusual functionalities including shape memory, superelasticity, and low/negative thermal ex- pansion. These properties have many advanced applications, such as actuators, sensors, and energy conversion, but are limited typically in a narrow temperature range of tens of Kelvin. Here we report that, by creating a nano-scale concentration modulation via phase separation, the MT can be rendered continuous by an in-situ elastic confinement mechanism. Through a model titanium alloy, we demon- strate that the elastically confined continuous MT has unprecedented properties, such as superelasticity from below 4.2 K to 500 K, fully tunable and stable thermal expansion, from positive, through zero, to negative, from below 4.2 K to 573 K, and high strength-to-modulus ratio across a wide temperature range. The elastic tuning on the MT, together with a significant extension of the crystal stability limit, provides new opportunities to explore advanced materials.
To further investigate the influence of metal ions on the allylic rearrangement of 3,4,5,6-tetrahydrophthalic an- hydride during the hydrothermal reaction, metal ions such as manganese（Ⅱ）, zinc（Ⅱ） and cadmium（Ⅱ） have been employed in the synthesis, which leads to the formation of three new lamellar coordination polymers, [MnⅡs（μ3-OH）3（1-chec）（1,2-chedc）（2,3-chedc）2（H20）] （3Mn）, [ZnⅡs（μ3-OH）3（1-chec）（1,2-chedc）（2,3-chedc）2（H20）] （4Zn）, and [CdⅡ3（μ3-OH）2（1,2-chedc）2] （5Cd） （1-chec=cyclohexene-l-carboxylate, 1,2-chedc=cyclohexene-1,2- dicarboxylate, 2,3-chedc=cyclohexene-1,2-dicarboxylate）. Interestingly, the allylic rearrangement reaction is metal-dependent, which occurs only in 3Mn and 4Zn, resulting in the formation of one chiral carbon atom of the corresponding dicarboxylate ligands in both compounds. In addition, the magnetic property of compound 3Mn was studied, which revealed strong antiferromagnetic interactions between the metal centers.
