Stresses in quenched ionic crystals. I. Theory

Abstract

Equations are set up describing the development of longitudinal stress as a function of time in a crystal down-quenched under conditions of plane strain. The effects of heat flow in one and two dimensions and of finite heat transfer coefficients are considered. Numerical results are obtained for NaCI.

A cinematographic study of the quenching process in ionic crystals

“…According to this model the rate of fall of temperature 0 on the axis of a specimen in which the heat flow is biaxial is as shown in figure 3 (Keeley 1971) where 00 is the initial temperature and the temperature of the quenching bath is zero. The initial rate of fall of temperature depends only on the reduced heat transfer coefficient h =LH/A, where H is the heat transfer coefficient and h is the thermal conductivity.…”

Stresses in quenched ionic crystals. II. Experiment

“…Theoretical studies (Keeley et al 1975) show that the stress distribution in a quenched solid is governed by the value of the 'reduced' heat transfer coefficient h and of the severity of quench parameter SQP. h is equal to HLIX, where H is the heat transfer coefficient, 2L is the specimen width and X is the thermal conductivity.…”

“…Let a parallel beam of monochromatic light pass normally through a crystal placed between a polarizer and analyser. If the polarizer and analyser transmit only radiation with its plane of vibration containing their respective vibration directions, even if some of this radiation is absorbed, it is readily shown (Keeley 1971) that the phase difference A is given by sin2 (Aj2) = I Zp/IpJpc.…”

“…In a previous paper (Keeley et al 1975) a calculation was made of the development of longitudinal stress and of the residual stress at equilibrium in down-quenched ionic crystals, using numerical values for NaC1. Equations were derived applying to both oneand two-dimensional heat flow.…”