A microstructure consisting of ultrafine grained (UFG) ferrite with average grain size of ~ 0.7 µm and dispersed nano-sized carbides was produced by cold-rolling and tempering of the martensite starting microstructure in a low carbon steel. Subsequently, fine grained dual phase (DP) steel consisting of equiaxed ferrite grains with average size of ~ 5 µm and martensite islands with average size ...

Ti-6Al-4V titanium alloy has great application in medicine and military industries due to its capabilities, namely high strength to weight ratio and corrosion resistance. In the current research, the effect of aging treatment on microstructure and wear behavior of Ti-6Al-4V titanium alloy was investigated. Pin on disk wear test was applied to assess the wear behavior. Specimens were first solut...

Precipitation-hardened (PH) stainless steels have been widely used as structural materials and related applications in marine environments, power plants (light-water and pressurized water reactors), and chemical industries because of their good mechanical properties and corrosion resistance at typical service temperatures below 300oC. 17-4 PH (A1S1630) stainless steel (15–17.5 Cr, 3–5 Ni, 3–5 C...

The objective of this work was to study materials subjected to external loading where alternative deformation mechanisms are available to generate strains. In the case of shapememory and superelastic NiTi, these mechanisms are twinning and stress-induced phase transformation, respectively. Superelastic NiTi (51.0 at.% Ni) reinforced with 0, 10 and 20 vol.% TiC particles was fabricated by Hot Is...

Laser powder bed fusion (L-PBF)-processed 17-4 PH stainless steel (SS) generally exhibits a non-equilibrium microstructure consisting mostly of columnar δ-ferrite grains and substantial fraction retained austenite martensite, contrary to SS wrought with fully martensite structure coarse grains. Despite the different microstructures L-PBF SS, post-processing is typically performed using conventi...

The standard heat treatment of PH 13-8 Mo maraging steels consists solution annealing and subsequent aging. Herein, it is investigated how an additional intercritical step prior to aging affects the microstructure, and, consequently, mechanical properties a steel. In situ techniques by means high-temperature electron backscatter diffraction X-ray are applied study microstructural changes during...

Cu-Al-Ni single crystals with composition 82.6Cu-13.4A1-4Ni (wt%) were heat treated at 800°C for 30 rnin and subsequently water quenched to room temperature. The samples with 3 mm diameter and length between 100 and 200 mm had a longitudinal orientation close to the [001] direction of the P-phase at high temperature. The martensite start temperature after the initial heat treatment was MS=93"C....

In this paper we present a walking pattern filter for Shape Memory Alloy (SMA) actuated biped robots. SMAs are known for their slow response. The actuation speed limitation can potentially lead to stability problems for biped robots. This filter adapts the human motion for a SMA biped in order to have a stable walking pattern. The Zero Moment Point (ZMP) is used as a main criterion of the filte...

Mechanical devices are sought to support insufficient or paralysed striated muscles including the failing heart. Nickel-titanium alloys (nitinol) present the following two properties: (i) super-elasticity, and (ii) the potential to assume different crystal structures depending on temperature and/or stress. Starting from the martensite state nitinol is able to resume the austenite form (state of...

The role of microstructural damage in controlling the edge stretchability of Complex-Phase (CP) and Dual-Phase (DP) steels was evaluated using hole tension experiments. The experiments considered a tensile specimen with a hole at the center of specimen that is either sheared (sheared edge condition) or drilled and then reamed (reamed edge condition). The damage mechanism and accumulation in the...