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.

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.

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.

Effect of annealing heat treatment on microstructure and mechanical properties of nonequiatomic CoCrFeNiMo medium-entropy alloys prepared by hot isostatic pressing

In this study, nonequiatomic Co28.5Cr21.5Fe20Ni26Mo4 medium-entropy alloys (MEAs) were prepared using hot isostatic pressing. The effect of annealing heat treatment on microstructure and mechanical properties of MEAs was investigated. The results showed that the microstructure of as-sintered alloys was mainly composed of the face-centered cubic (FCC) phase and μ phase. The presence of the μ phase could improve the compressive strength of Co28.5Cr21.5Fe20Ni26Mo4 MEAs. Meanwhile, the ductile FCC phase matrix could effectively suppress the propagation of cracks to improve its ductility. Hence, as-sintered MEAs possessed excellent compression properties, and the average compressive strength value was 2,606 MPa when the strain was 50%. Compared with as-sintered MEAs, the phase composition of as-annealed MEAs did not change. The micro-hardness of annealed MEAs was stable compared to as-sintered MEAs (342 HV), and its fluctuation was about ±30 HV. The compressive strength of the annealed MEAs did not alter greatly, and the maximum fluctuation value was only about 6.5%. Hence, Co28.5Cr21.5Fe20Ni26Mo4 MEAs had excellent thermal stability.

Modeling of Annealing Heat Treatment Parameters for Zr Alloy Tube by ANN-Ga

In this paper, there are tow part of module for predicting the Annealing heat treatments of Zr tube. The artificial neural network (ANN) were used for relationship between mechanical property and annealing parameters. The genetic algorithm (GA) were used for Annealing heat treatments of Zr tube. The best ANN network architecture is 2-8-3, and the optimum values of momentum factor is 0.8 while the Crossover is also 0.8 by ANN-GA, which can be efficiently track the effect of annealing Heat treatment on properties for Zr-4 alloy. Keywords: Zr alloy, Heat Treatment, mechanical propert

Effect of Annealing Heat Treatment on the Microstructural Evolution and Mechanical Properties of Hot Isostatic Pressed 316L Stainless Steel Fabricated by Laser Powder Bed Fusion

In this work, the microstructural features and mechanical properties of an additively manufactured 316L stainless steel have been determined. Three types of samples were characterized: (i) as printed (AP), (ii) annealing heat treated (AHT), and (iii) hot isostatic pressed and annealing heat treated (HIP + AHT). Microstructural analysis reveals that the AP sample formed melt pool boundaries with nano-scale cellular structures. These structures disappeared after annealing heat treatment and hot isostatic pressing. The AP and AHT samples have similar grain morphologies; however, the latter has a lower dislocation density and contains precipitates. Conversely, the HIP + AHT sample displays polygon-shaped grains with twin structures; a completely different morphology compared to the first two samples. Optical micrography reveals that the application of hot isostatic pressing reduces the porosity generated after laser processing. The tensile strengths of all the samples are comparable (about 600 MPa); however, the elongation of the HIP + AHT sample (48%) was superior to that of other two samples. The enhanced ductility of the HIP + AHT sample, however, resulted in lower yield strength. Based on these findings, annealing heat treatment after hot isostatic pressing was found to improve the ductility of as-printed 316L stainless steel by as much as 130%, without sacrificing tensile strength, but the sample may have a reduced (40%) yield strength. The tensile strength determined here has been shown to be higher than that of the hot isostatic pressed, additively manufactured 316L stainless steel available from the literature.