Investigations on the Influence of Annealing on Microstructure and Mechanical Properties of Electrodeposited Ni-Mo and Ni-Mo-W Alloy Coatings

Ni-Mo and Ni-Mo-W coatings were electrodeposited on a stainless steel sheet, and then were annealed at 200, 400, and 600 °C. The effect of annealing heat treatment on the microstructure of Ni-Mo and Ni-Mo-W electrodepositions, their nano-hardness, and tribological properties were investigated. It was revealed that the average crystalline are refined and phase separation are promoted with formation of Mo-W related intermetallic precipitates at temperature exceed 400 °C on account of the co-existence of Mo-W elements within Ni-Mo-W coatings. Annealing heat treatment leads to hardening, and the hardness and elastic module increase significantly. The grain boundary (GB) relaxation and hard precipitated intermetallic particles are responsible for the annealing-induced hardening for ≤400 °C annealed and 600 °C annealed Ni-Mo-W coatings, respectively. In addition, both adhesive wear and abrasive wear are observed for coatings, and abrasive wear becomes predominant when annealing temperature up to 600 °C. The wear resistance of coatings is improved eventually by formation of a mixture of lubricated oxides upon annealing at 600 °C and the enhancement of H/E ratio for ≤400 °C annealed Ni-Mo-W coatings.

Hydrogen Diffusion Influence on the Stabilizing Phases Behavior in the Ti-6Al-4V Alloy

For obtaining a unique microstructure in Ti-6Al-4V, hydrogen is utilized as a temporary alloying element; therefore, the mechanism of hydrogen diffusion in α and β phases should be understood. In this study, the electrochemical hydrogenation was applied to the half-length of thin titanium rods, and the diffusion annealing heat treatment was implemented at different temperatures. The hydrogen diffusion coefficient of α phase (Dα) and the hydrogen diffusion coefficient of β phase (Dβ) was determined by employing Abaqus software and C# program for three different homogeneous microstructures. The obtained results showed that Dβ increases, and Dα decreases when the hydrogen concentration in β phase increases. Furthermore, it was observed that each microstructure has a specific temperature in which the maximum hydrogen amount is absorbed. The hydrogen uptake depends more on the volume fraction of β phase than the volume fraction of α phase, which is considered an obstacle to hydrogen diffusion in this alloy.

Effect of austenite reverted transformation-annealing heat treatment on microstructure and mechanical properties of Fe–0.14C–5Mn–1Al–Ce steel

Microstructure and mechanical properties of medium-Mn steel (Fe–0.14C–5Mn–1Al–Ce) processed by different austenite reverted transformation-annealing temperatures vary from 580 °C to 740 °C were studied. It was found that the austenite reverted transformation-annealing temperature has a strong effect on microstructure evolution. The martensite structure was transformed into austenite by austenite reverted transformation during the austenite reverted transformation-annealing process. The orientation relationship between the austenite and the matrix was dominated by the Kennicutt–Schmidt relation. With the increase of the austenite reverted transformation-annealing temperature, the content of retained austenite first increases and then decreases at room temperature. The tensile strength first decreases and then increases, while the elongation first increases and then decreases. An excellent combination of tensile strength and elongation (Rm × A) was obtained in the Fe–0.14C–5Mn–1Al–Ce steel by austenite reverted transformation-annealing at 640 °C.

Experimental and extended finite element simulations for tensile fracture phenomenon of cryorolled aluminium alloy 5754

In present work, cryorolling is performed to obtain the higher mechanical strength of the received material. Close to 50% and 30% increments in tensile and yield strengths of the material are observed for 40% thickness reduction. However, limited ductility has been obtained for cryorolled samples. Post annealing heat treatment is performed on cryorolled samples to obtain combined enhancement in strength and ductility of the alloy. Difference in the ductile fracture along with crack initiation and its advancement with plastic straining is also compared for cryorolled and annealed cryorolled samples. Fracture angle and crack propagation behavior at vicinity of gauge section is evaluated by using extended finite element method (XFEM) and compared with experimental tested work piece. XFEM has been adopted to simulate the crack growth behavior from nucleation till fracture of the investigated alloy. Triaxial stress contour plots are also captured by XFEM near to the crack initiation zone.

Shape Memory and Mechanical Properties of Cold Rolled and Annealed Fe-17Mn-5Si-5Cr-4Ni-1Ti-0.3C Alloy

In the present study, the shape, memory, and mechanical properties of cold-rolled and annealed Fe-17Mn-5Si-5Cr-4Ni-1Ti-0.3C (wt.%) alloy were investigated. The cold-rolled alloy was annealing heat-treated at different temperatures in the range of 500–900 °C for 30 min. The shape recovery behavior of the alloy was investigated using strip bending test followed by recovery heating. The microstructural evolution and the stress-strain response of the alloy heat-treated at different temperatures revealed that the recovery took place at a heat-treatment temperature higher than 600 °C. Recrystallization occurred when the heat-treatment temperature was higher than 800 °C. Meaningful shape recovery was observed only when the alloy was annealed at temperatures higher than 600 °C. The highest recovery strain of up to 2.56% was achieved with a pre-strain of 5.26% and recovery heating temperature of 400 °C, when the alloy was heat-treated at 700 °C. Conversely, the yield strength reduced significantly with increasing annealing heat-treatment temperature. The experimental observations presented in this paper provide a guideline for post-annealing heat-treatment when a good compromise between mechanical property and shape recovery performance is required.

Microstructure after Solution Annealing of the Nuclear Grade Austenitic Stainless Steel DIN 1.4970

The main objective of the present work was to characterize the phases that are present after solution annealing in the microstructure of the titanium stabilized austenitic stainless steel W.-Nr. 1.4970, developed as a candidate material for fast breeder reactor fuel cladding. The crystalline structure, chemical composition, quantity, size, morphology, and distribution of the phases present in the microstructure after solution annealing heat treatments were studied in detail with the help of several complementary techniques. Chemical dissolution of the matrix has been performed using the Berzelius solution and the extracted residue has been analyzed by X-ray diffraction in a high precision camera. Three phases have been observed and identified after solution annealing heat treatments performed in the 1090 to 1300 °C temperature range, namely: (Ti,Mo)C; Ti (N,C) and Ti4C2S2. The Ti-nitride and the Ti-carbosulfide did not dissolve in the steel matrix up to 1300 °C, on the other hand, the solubility of the (Ti,Mo)C raised strongly with temperature. A solution annealing heat treatment is recommended for the W. Nr. 1.4970 stainless steel.

Effects of zirconium addition on electrochemical and mechanical properties of Mg-3Zn-1Ca-1RE alloy

Purpose The effect of zirconium, zinc, calcium and rare earth group as the alloying elements on mechanical properties and corrosion behavior of magnesium alloys was investigated in the simulated body fluid. Design/methodology/approach Pure magnesium and the alloying elements were melted and zirconium was finally added to obtain different alloys. The castings were annealed and some samples were aged heat treated. X-ray fluorescence was used for the elemental analysis and LSV was used for electrochemical corrosion evaluations. Findings Results showed that corrosion resistance decreases with increasing zirconium content. The lowest corrosion rate was obtained for the samples containing 0.3% and 0.45% of Zr from annealed and aging heat-treated samples, respectively. Yield stress enhances with increasing the zirconium content and degrades by the aging heat treatment. Originality/value These alloys were studied for the first time. Effect of casting without using protective flux and vacuum furnaces. Effect of annealing at 440°C for 2 h and artificial aging at 200°C for 16 h. Alloy’s electrochemical behavior on the body’s simulation environment has been investigated. Improvement of mechanical properties after annealing heat treatment by high zirconium percentage.

Pengaruh Annealing terhadap Sifat Keras dan Struktur Mikro Baja Tahan Karat AISI 410-3Mo-3Ni

AISI 410-3Mo-3Ni stainless steel is a martensitic steel which limited in using when compared to austenitic and ferritic stainless steels. Martensitic steel has an essential role in specific components due to a combination of strength, toughness and excellent corrosion resistance. However, martensitic steel tends to undergo decreasing in mechanical properties and microstructure after the forging process. In this study, mechanical properties and microstructure of the forged AISI 410 after receiving annealing heat treatment will be studied. Annealing aims to reduce material hardness and increase grain refinement of material. Annealing heat treatment is carried out by varying the annealing temperature and time. Annealing temperature variations are 7000, 7600, and 8000C. The annealing time variation is 3 hours and 6 hours. The effect of annealing time and temperature will be studied on the hardness and microstructure of the AISI 410 modified material. The optimum hardness of 35.9 HRC in sample with annealing treatment in 760°C for 6 hours. The microstructure shows delta ferrite, martensite, austenite, and carbide phases which affect hardness value of annealed samples.