A nanoindentation study of magnetron co-sputtered nanocrystalline ternary nitride coatings

Nanoindentation testing was used to determine the hardness, elastic modulus and plasticity parameter of three newly developed ternary nitride coatings with nano-sized grains. With decreasing nitrogen deposition pressure, grain diameter of the coatings decreases that leads to both higher nanohardness and elastic modulus with conservation of satisfactory values of plasticity characteristic

Plasticity of materials determined by the indentation method

In this review, the development of techniques for determining the plasticity of mate rials by the indentation is considered.У даному огляді розглянуто розвиток метод визначення пластичности матеріялів індентуванням.В данном обзоре рассмотрено развитие методик определения пластичности материалов индентированием

Application of the Martel dynamic hardness to the penetration problem

Penetration of the undeformable kinetic energy projectile (KEP) into the target is considered as the “deep” indentation. It was shown by the example of aluminum alloys that the Martel dynamic hardness HMRd can be used for description of this process.Проникнення недеформівним кінетичним індентором (KEP) в цілому можна розглядати як “глибоке” індентування. На прикладі алюмінієвих сплавів було показано, що динамічна твердість за Мартелем HMRd може бути використана для опису цього процесу.Проникновение недеформируемым кинетическим индентором (KEP) в целом можно рассматривть как "глубокое" индентирование. На примере алюминиевых сплавов показано, что динамическая твердость по Мартелю HMRd может быть использована для описания этого процесса

Influence of the cooling rate on the structure and mechanical properties of a cast alloy of Al-Mg-Si system

An investigation of influence of the cooling rate on the structure and hardness of a new cast eutectic (α-Al + Mg2Si) alloy of the Al—Mg—Si ternary system showed that the critical cooling rate at which a colonial eutectic structure disappears is ~10^5 K/s. The change-over from laboratory castings with a weight of 200g to commercial castings with a weight of 20 kg practically does not influence on the level of mechanical properties under comparable cooling conditions

Temperature and Orientation Dependence of Yield Stress and Plasticity in Molybdenum Single Crystals of High Purity

In order to study the influence of purification on the strength and plasticity of molybdenum single crystals in bending tests, the investigation was carried out on crystals of 6 orientations and two purity levels (r293K/r4.2K=95000 and 2000 respectively) in the temperature range from 77K to 373K. The dependence of yield stress and ductile-brittle transition temperature on crystal orientation and purity was established. The results are discussed in connection with the peculiarities of dislocation slip and multiplication in bending which are illustrated by X-ray epigrams

Construction of stess-strain curves for brittle materials by indentation in a wide temperature range

A test method procedure for constructing stress-strain curves by indentation of brittle and low plastic materials under temperature ranging from 20 to 900°C was developed recently by Yu. Milman, B. Galanov et al. According to this test method procedure stress-strain curves σ - Є for Si, Ge, SiC, TiB2 and WC/Co hard alloy were constructed in the above temperature region and mechanical parameters such as elastic point, σe, yield stress, σs, etc. were extracted by using the measurement results obtained by a set of trihedral pyramid indenters with different angles at the tip, γ1, ranging from 45 to 85°C

Application of the plasticity characteristic determined by the indentation technique for evaluation of mechanical properties of coatings: II. guidelines to coating development and processing control

The equilibrium between solid and 1iquid phases in sintered composite materials has been studied. It is shown that closed surfaces, which bound dispersed phases, influence the mechanical equilibrium between these phases. An expression is derived for a dihedral angle in composite materials, which includes values of surface tensions at the phase interfaces as well as parameters of a composite equilibrium structure (phase composition, particle contiguity and coefficients of a particle geometry).

ПРИМЕНЕНИЕ КВАЗИКРИСТАЛЛИЧЕСКОГО ПОКРЫТИЯ ДЛЯ ПОВЫШЕНИЯ ЖАРОСТОЙКОСТИ ПОРШНЕВОГО АЛЮМИНИЕВОГО СПЛАВА

The results of experimental investigations of heat resistance of piston aluminum alloy with quasicrystalline coating tested in a gas-dynamic stand DTC-1 are resulted. The temperature of surface and volume destruction effected by directional flow of the combustible mixture is determined. It is shown that the quasicrystalline coating on aluminum alloy allows to increase the working temperature on ~250 ° C.  Приведены результаты экспериментальных исследований жаростойкости поршневого алюминиевого сплава с квазикристаллическим покрытием при испытании на газодинамическом стенде ДКН-1. При проведении эксперимента определяли температуру, при которой визуализируются поверхностно-объемные разрушения образца под воздействием направленного потока горючих газов. Показано, что нанесение квазикристаллического покрытия на сплав алюминия позволяет на ~ 250 °С повысить рабочие температуры эксплуатации, при которых не наблюдается деградация поверхности при испытаниях в потоке горючей смеси.