This investigation concerns the application of profilometry‐based indentation plastometry (PIP) to metals with very high hardness, i.e., those with yield stresses of 1.5–3 GPa. The PIP procedure comprises (a) applying a force to an indenter ball, penetrating the sample to a preselected depth, (b) measuring the profile of the indent, and (c) iteratively running a finite element method (FEM) model to obtain the true stress–true strain curve giving optimal agreement between measured and modeled profiles. The procedure is no different when the sample is very hard, although the ball must remain elastic during the process. It is shown that this can be achieved using silicon nitride balls. These can fracture under some conditions, but it is shown that a “proof‐testing” operation can be used to ensure that any particular ball will remain elastic under the complete range of service conditions. It is also shown, via systematic comparisons with the outcomes of uniaxial (tensile and compressive) tests, that reliable stress–strain curves can be obtained for very hard metals. Furthermore, PIP testing has advantages over uniaxial testing for obtaining information about their behavior at relatively high strains (≈15%), as well as being much easier and simpler to implement.

This investigation concerns the application of the profilometry‐based indentation plastometry (PIP) methodology to obtain stress–strain relationships for material in the vicinity of fusion welds. These are produced by The Welding Institute (TWI), using submerged arc welding to join pairs of thick steel plates. The width of the welds varies from about 5 mm at the bottom to about 40–50 mm at the top. For one weld, the properties of parent and weld metal are similar, while for the other, the weld metal is significantly harder than the parent. Both weldments are shown to be approximately isotropic in terms of mechanical response, while there is a small degree of anisotropy in the parent metal (with the through‐thickness direction being slightly softer than the in‐plane directions). The PIP procedure has a high sensitivity for detecting such anisotropy. It is also shown that there is excellent agreement between stress–strain curves obtained using PIP and via conventional uniaxial testing (tensile and compressive). Finally, the PIP methodology is used to explore properties in the transition regime between weld and parent, with a lateral resolution of the order of 1–2 mm. This reveals variations on a scale that would be very difficult to examine using conventional testing.

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Herein, it is concerned with the use of profilometry‐based indentation plastometry (PIP) to obtain mechanical property information for particulate metal matrix composites (MMCs). This type of test, together with conventional uniaxial testing, has been applied to four different MMCs (produced with various particulate contents and processing conditions). It is shown that reliable stress–strain curves can be obtained using PIP, although the possibility of premature (prenecking) fracture should be noted. Close attention is paid to scale effects. As a consequence of variations in local spatial distributions of particulate, the “representative volume” of these materials can be relatively large. This can lead to a certain amount of scatter in PIP profiles and it is advisable to carry out a number of repeat PIP tests in order to obtain macroscopic properties. Nevertheless, it is shown that PIP testing can reliably detect the relatively minor (macroscopic) anisotropy exhibited by forged materials of this type.

A formulation is proposed for true stress–true strain relationships in the plastic regime that exhibit sigmoidal shapes, such as those of certain metastable austenitic stainless steels (MASS). It contains two terms, broadly accounting for contributions to hardening from conventional plasticity and from mechanical stimulation of martensite formation. It is a continuous function, designed to cover the plastic strain range from zero up to several tens of percent. It is shown that it is suitable for capture of a range of curve shapes of this type—experimental data from tensile testing of a MASS alloy over a range of temperature, with good fidelity. The formulation incorporates six independent parameters, although there may be scope for limiting the range of values that they can have, facilitating convergence operations. Information is presented about how convergence is obtained. The equation is thus expected to be suitable for use in finite element method (FEM) models for simulation of plastic deformation in various scenarios, including indentation. Future work will involve exploration of the details of this.