The mechanical properties of polycrystalline diamond as a function of strain rate and temperature

Abstract

Polycrystalline diamond (PCD) materials are used in various applications, mainly as cutting tools for machining non-ferrous metals and non-metallic materials and for rock drilling operations. A better knowledge of their mechanical properties is of fundamental importance to PCD manufacturers and end users. In order to understand and predict the behaviour and structural integrity of the tools containing PCD, it is first necessary to study the behaviour of the material as a function of loading rate and temperature.In this paper, material behaviour is determined under testing conditions which correspond more closely to those in actual drilling, which is a significant improvement over investigations to date. Young's modulus determined by four-point bending and a split-Hopkinson pressure bar apparatus was relatively constant with the rate, while a consistent decrease was observed with increase of temperature. The flexural strength was found to increase with the temperature, while decreasing with an increase in rate.

A combined experimental–numerical investigation of fracture of polycrystalline cubic boron nitride

“…the expense of high temperature gauges needed to evaluate fracture toughness at high rates. Petrović [22] has successfully used these high temperature gauges to measure the dynamic fracture properties of PCD up to 650 It should be noted that Figures 6 and 7 plot apparent or measured fracture toughnesses, denoted K b rather than the critical fracture toughness, denoted K c . It is known that the effect of the blunt notch plays a role in the systematic overestimation of the fracture toughness [23].…”

Fracture mechanisms of polycrystalline advanced ceramics

“…Choice of loading rates between quasistatic and the highest dynamic rate was taken as a uniform distribution across five decades of the loading rate in logarithmic scale. Three temperature levels were employed: 25, 300 and 600°C [8], with the highest temperature appearing in real operating conditions [9,10]. At least three and no more than 5 repetitions were carried out at each possible combination of five loading rates and three temperature levels.…”

Flexural Strength Reduction in Cemented Carbides

“…The series of tests on laser-cut cemented carbide specimens were previously performed in laboratory conditions at room temperature. Loading rate was varied from quasistatic of 1 mm/min up to dynamic of 5 m/s using the same procedure as outlined earlier in [1,2]. Using standard equations, the fracture toughness, fracture energy, flexural strength and Young's modulus were determined according to linear elastic fracture mechanics.…”