Topological Model for Boroaluminosilicate Glass Hardness

Abstract

For various advanced glass applications, it is important to understand the composition dependence of indentation hardness. Boroaluminosilicate glasses form the basis of many industrial products and they exhibit complex structural behavior due to the mixed networkformer effect. Based on available structural nuclear magnetic resonance data and a previously proposed approach, we here establish a temperature-dependent constraint model of indentation hardness of sodium boroaluminosilicate glasses. The model correctly predicts the trends of hardness with varying Si/Al and Na/B ratios, including local minima and maxima at intermediate compositions. This topological approach is thus proving to be a valuable tool for exploring and designing new boroaluminosilicate glass compositions with tailored hardness.

Modifier Interaction and Mixed-Alkali Effect in Bond Constraint Theory Applied to Ternary Alkali Metaphosphate Glasses

“…More recently, Gupta and Mauro (2009) and Mauro et al (2009) introduced the concept of temperature-dependent constraints, based on previous work by Naumis (2005,2006), taking into account the temperature dependence of configurational entropy and, hence, the number of bond constraints. This allowed for applying constraint counting to calculate the compositional trends of properties, such as the glass transition temperature Mauro et al, 2009;Smedskjaer et al, 2010bSmedskjaer et al, , 2011Fu and Mauro, 2013;Jiang et al, 2013;Wondraczek, 2013, 2014;Hermansen et al, 2014a;, fragility Mauro et al, 2009;Hermansen et al, 2014a), and surface hardness (Smedskjaer et al, 2010a(Smedskjaer et al, ,c, 2011Wondraczek et al, 2011;Smedskjaer, 2014). While useful applications of the BCT need detailed structural information, the strength of this approach lies in its simplicity, as only the knowledge of the components' first shell coordination number and a reasonable guess about the relative strength of the constraints considered are required for relatively accurate property prediction.…”

Rigidity Transition in Materials: Hardness is Driven by Weak Atomic Constraints

“…Indeed, by capturing the chemical details of glasses that are relevant to macroscopic properties while filtering out those that are not, rigidity theory [13][14][15] has been used to predict the composition dependence of hardness, H, which characterizes resistance to permanent deformations under a load. Hence, topological constraint theory is a promising tool for designing stronger materials, which has recently been identified as a "grand challenge" for the future [16][17][18].…”

Microstructural and Dynamical Heterogeneity Characteristics in Al2O3- 2SiO2 Liquid

“…Fig 2 shows In Fig 3, we can see distribution of TO n (T= Si, Al) coordination units in liquid AS2 system as a function of pressure. At ambient, the number of SiO 4 , AlO 3 and AlO 4 unit is domain. As temperature increases the fraction of SiO 4 , AlO 3 and AlO 4 decreases meanwhile the fraction of TO 5 , TO 6 (T= Si, Al) units increases in considered pressure interval.…”

“…At ambient, the number of SiO 4 , AlO 3 and AlO 4 unit is domain. As temperature increases the fraction of SiO 4 , AlO 3 and AlO 4 decreases meanwhile the fraction of TO 5 , TO 6 (T= Si, Al) units increases in considered pressure interval. It means that increasing pressure, there is a transformation from four-fold coordination (TO 4 ) to five-and six-fold coordination (TO 5 and TO 6 ).…”

“… Silicate, glass-forming mixtures of SiO 2 with an oxide such as Al 2 O 3 , Na 2 O, or K 2 O are an important class of materials used in many technological applications [1][2][3][4]. Therefore the microstructure and dynamical properties of liquid silicates have been studied by many experiments, theory and simulation.…”