Excellent Combination Of Ductility Research Articles

Microstructure and mechanical properties of TiNbV0.5Ta0.5Crx (x=0, 0.1, 0.2, 0.5) refractory high-entropy alloys

The TiNbV0.5Ta0.5Crx (x = 0, 0.1, 0.2, 0.5) refractory high-entropy alloys (RHEAs) with an excellent combination of ductility and strength were designed and prepared for high-temperature applications. The yield strength, ultimate tensile strength, and elongation of the TiNbV0.5Ta0.5Cr0.1 alloy were 878 MPa, 928 MPa, and 21.6 %, respectively. Important issues of microstructure evolution, precipitation process, and their impact on mechanical properties were concerned. Then, the effect of Cr content on the mechanical properties of TiNbV0.5Ta0.5Crx alloys was evaluated through a quantitative analysis of the strengthening mechanism, which elucidated the trade-off relationship between solid solution strengthening and precipitation strengthening in RHEA. The microstructure evolution of the TiNbV0.5Ta0.5Crx alloys involved the formation and interconversion of titanium allotropes (α-Ti and β-Ti) and the precipitation of the Laves phase. Significant embrittlement was induced by the preferential precipitation of α-Ti on the grain boundary. The TiNbV0.5Ta0.5Crx alloys exhibited an incubation period for Laves phase precipitation, which was related to the Cr content in the alloy. The Laves phase preferentially nucleated next to α-Ti due to the redistribution of elements during the α-Ti precipitation process. The precipitation of the Laves phase played an important role in enhancing the strength of the TiNbV0.5Ta0.5Crx alloys.

Influence of texture and microstructural evolution on ductility and tensile behaviour of annealed Zircaloy-4 processed through swaging

The critical study is focused on improving ductility by maintaining higher strength of swaged Zircaloy-4 through specifically optimized annealing treatment. It has led to evolution of texture to obtain stable (21¯1¯0) pyramidal type in the microstructure, enhanced elongation up to ∼20%. An excellent combination of ductility and strength was achieved through low-strain-swaging followed by annealing optimization, unlike other resource-intensive and conventional SPD techniques. Improvements in mechanical properties, especially ductility enhancement, were substantiated with the detailed and targeted microstructural analysis with EBSD and TEM.

Machine Learning-Based Strength Prediction for Refractory High-Entropy Alloys of the Al-Cr-Nb-Ti-V-Zr System.

The aim of this work was to provide a guidance to the prediction and design of high-entropy alloys with good performance. New promising compositions of refractory high-entropy alloys with the desired phase composition and mechanical properties (yield strength) have been predicted using a combination of machine learning, phenomenological rules and CALPHAD modeling. The yield strength prediction in a wide range of temperatures (20–800 °C) was made using a surrogate model based on a support-vector machine algorithm. The yield strength at 20 °C and 600 °C was predicted quite precisely (the average prediction error was 11% and 13.5%, respectively) with a decrease in the precision to slightly higher than 20% at 800 °C. An Al13Cr12Nb20Ti20V35 alloy with an excellent combination of ductility and yield strength at 20 °C (16.6% and 1295 MPa, respectively) and at 800 °C (more 50% and 898 MPa, respectively) was produced based on the prediction.

Effect of Annealing Temperature on Austenite Stability of a δ-TRIP Steel

In this work, a novel type of δ-TRIP steel was designed, and the content and stability of retained austenite in δ-TRIP specimens under different annealing processes were detected and studied, respectively. The volume fraction of austenite was determined by X-ray diffraction (XRD). The microstructure and mechanical properties were analyzed systematically. The results show that a complex microstructure composed of three phases (ferrite, bainite and retained austenite) was obtained in the δ-TRIP steel. With the increasing of annealing temperature, both retained austenite and bainite content in the specimen increased, while the carbon content in retained austenite decreased, leading to a poor stability for retained austenite. Both tensile and yield strength improved with the increasing of annealing temperature, while the elongation reduced. The feature of retained austenite led to an excellent combination of ductility and strength, which was better than traditional TRIP steel.

A promising CoFeNi2V0.5Mo0.2 high entropy alloy with exceptional ductility

A novel high entropy alloy with the composition of CoFeNi2V0.5Mo0.2, shows unusual strain hardening ability and an excellent combination of ductility and strength. Especially at 873 K, the elongation can reach 189.2%, almost three times that of the common high temperature alloys. Microstructural characterization suggests a coexistence of planar slip and cross slip. The resistance of planar slip serves to strengthen the alloy, while the cross slip effectively relieves strain concentration, substantially contributing to the uniform elongation. Also, the interaction of planar slip and cross slip will lead to the formation of two kinds of dislocation loops.

INCOLOY ALLOY 945 AND 945X

Abstract Incoloy Alloy 945 is a nickel-base precipitation-strengthened alloy that provides 860 MPa (125 ksi) minimum yield strength and an excellent combination of ductility and impact strength. The nickel content is sufficient to provide protection against chloride-ion stress-corrosion cracking. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ni-666. Producer or source: Special Metals Corporation. Originally published December 2008, revised April 2014.

TiAlNb-alloy with a modulated B19 containing constituent produced by powder metallurgy

ABSTRACTIntermetallic TiAl alloys are of interest to the aero engine industry because of their light weight, corrosion resistance and excellent high temperature strength. This justifies the continued effort to improve properties and processing of these alloys.A critical parameter that limits the practical implementation of Ti aluminides is their low ductility at room temperature. Recently, a new class of TiAl alloys based on a modulated lath structure has been introduced that exhibit an excellent combination of ductility and strength. A key component in this alloy is the orthorhombic phase B19 that is attributed to alloying with high amounts of niobium. The driving forces and mechanisms that lead to the observed modulated structures involving the B19 phase are not fully understood yet. As a first step to a better understanding we present a study of the thermal stability range of the phases involved.