Radiation-induced amorphization is one of the concerns with SiC as structural components for next-generation nuclear reactors. Numerous studies have been focused on the amorphization mechanisms under electron, neutron, and ion irradiation. Proposed mechanisms for ion-induced amorphization include nucleation and growth of amorphous regions, direct impact combined with stimulated amorphization at...

Ni-implantation has been conducted for sputter deposited Zr alloy films to investigate compositional dependent amorphization behavior in proportion to Ni in Zr alloys. As-deposited Zr and Zr–Cu with thickness of 200 nm shows columnar hcp-Zr and nano-crystalline hcp-Zr(Cu), respectively. Implantation of 150 keV Niþ with the amount of 1 10 ions/cm induces amorphization of Zr and Zr(Cu) with 100 n...

The mechanism of milling-induced amorphization was studied by investigating the structural evolution during amorphization via high-energy ball milling of a chalcogenide compound, i.e. Ag3PS4 crystal. The gradual decrease in intensity of the XRD diffraction peaks of Ag3PS4 milled for different durations indicates that the degree of amorphization was enhanced by the mechanical milling. The forwar...

Dynamics of amorphization and fracture in SiSe 2 nanowires are studied using the molecular-dynamics method. We find that fracture is initiated in an amorphous region at the nanowire surface. Local amorphization propagates across the nanowire while multiple cracks start at the boundaries of the amorphous region. Results for the time evolution of amorphization, crack propagation, and fracture are...

We report depressurization amorphization of single-crystal boron carbide (B4C) investigated by in situ high-pressure Raman spectroscopy. It was found that localized amorphization of B4C takes place during unloading from high pressures, and nonhydrostatic stresses play a critical role in the high-pressure phase transition. First-principles molecular dynamics simulations reveal that the depressur...

Recent experimental and theoretical studies have shown an essential role of sulfur segregationinduced amorphization of crystalline nickel leading to its embrittlement at a critical sulfur concentration of 14%, but the atomistic mechanism of the amorphization remains unexplained. Here, molecular dynamics simulations reveal that the large steric size of sulfur impurity causes strong sulfur-sulfur...

Silicon dioxide has eight stable crystalline phases at conditions of the Earth's rocky parts. Many metastable phases including amorphous phases have been known, which indicates the presence of large kinetic barriers. As a consequence, some crystalline silica phases transform to amorphous phases by bypassing the liquid via two different pathways. Here we show a new pathway, a fracture-induced am...

It is extremely difficult to realize two conflicting properties-high hardness and toughness-in one material. Nano-polycrystalline stishovite, recently synthesized from Earth-abundant silica glass, proved to be a super-hard, ultra-tough material, which could provide sustainable supply of high-performance ceramics. Our quantum molecular dynamics simulations show that stishovite amorphizes rapidly...

Amorphous materials are used for both structural and functional applications. An amorphous solid usually forms under driven conditions such as melt quenching, irradiation, shock loading or severe mechanical deformation. Such extreme conditions impose significant challenges on the direct observation of the amorphization process. Various experimental techniques have been used to detect how the am...

Emulsified high-density amorphous ice, made by pressure-induced amorphization of emulsified ice Ih, was decompressed at about 160 K. The onset of an endothermic event was observed around 0.4 GPa during the decompression. This is consistent with existence of the glass transition to a liquid state, implying the close relationship between melting and amorphization.