ریزساختار و خواص مکانیکی آلیاژ تیتانیوم پس از عملیات حرارتی

Microstructure and mechanical properties of 

TC21 titanium alloy after heat treatment 

ریزساختار و خواص مکانیکی آلیاژ تیتانیوم TC21 پس از عملیات حرارتی

ABSTRACT

Microstructure evolutions during different heat treatments and influence of microstructure on mechanical properties of TC21 titanium alloy were investigated. The results indicate that the excellent mechanical properties can be obtained by adopting air cooling after forging followed by heat treatment of (900 °C, 1 h, AC)+(590 °C, 4 h, AC). Deformation in single β field produces pan-like prior β grains, while annealing in single β field produces equiaxed prior β grains. Cooling rate after forging or annealing in single β field and the subsequent annealing on the top of α+β field determine the content and morphology of coarse α plates. During aging or the third annealing, fine secondary α plates precipitate. Both ultimate strength and yield strength decrease with the content increase of coarse α plates. Decreasing effective slip length and high crack propagation resistance increase the plasticity. The crisscross coarse α plates with large thickness are helpful to enhance the fracture toughness.

 

اثر عملیات حرارتی بر ریزساختار و خواص مکانیکی آلیاژ فراریزدانه شبه تیتانیوم β

Effect of Heat Treatment on Microstructure and Mechanical

Properties of Ultra-fine Grained Ti-55511 Near β Titanium Alloy

اثر عملیات حرارتی بر ریزساختار و خواص مکانیکی آلیاژ فراریزدانه شبه تیتانیوم β 

ABSTRACT

The ultra-fine grained (UFG) Ti-55511 near β titanium alloy with grain size 0.1∼0.5 μm was prepared by hot rolling. The effects of heat treatment on the microstructure and mechanical properties were investigated using SEM and TEM. The results indicate that both strength and hardness increase firstly and then reduce with increasing of heat treatment temperature from 350°C to 650°C. The peak strength (1486 MPa) appears at 450°C. The strength dramatically reaches to 1536 MPa and then is stablized with increasing of the holding time when heat treated at 450°C. While the elongation increases firstly and then decreases. The microstructure analysis shows that the dynamic recovery occurs and the grain sizes remain at smaller than 1 μm during annealing. The recovery stimulates the grain refinement effect by eliminating the hardening process and stimulating the grain boundary/phase boundary to be stable. The phase transformation of α→α2 and β→ω→α enhances the second phase particle dispersion effect during annealing. However, the ductility of the alloy could significant decrease when the second phase particles grow up to a certain size. The mechanical properties evolution during annealing are mainly related to the effect of strengthening mechanisms.

 

ریزساختار و خواص مکانیکی Ti-5Al-2Sn-2Zr-4Mo-4Crعملیات حرارتی شده

Microstructure and mechanical properties of

heat-treated Ti–5Al–2Sn–2Zr–4Mo–4Cr

ریزساختار و خواص مکانیکی  Ti-5Al-2Sn-2Zr-4Mo-4Crعملیات حرارتی شده

ABSTRACT

The effects of heat treatment parameters on the microstructure, and mechanical properties and fractured morphology of Ti-5Al-2Sn-2Zr-4Mo-4Cr with the equiaxed, bi-modal and Widmanstätten microstructures were investigated. The heating temperatures for obtaining the equiaxed, bi-modal and Widmanstätten microstructures were 830, 890 and 920 °C, respectively, followed by furnace cooling at a holding time of 30 min. The volume fraction of primary α phase decreased with increasing the heating temperature, which was 45.8% at 830 °C, and decreased to 15.5% at 890 °C, and then the primary α phase disappeared at 920 °C during furnace cooling. The variation of volume fraction of primary α phase in air cooling is similar to that in furnace cooling. The increase in heating temperature and furnace cooling benefited the precipitation and growth of the secondary α phase. The equiaxed microstructure exhibited excellent mechanical properties, in which the ultimate strength, yield strength, elongation and reduction in area were 1035 MPa, 1011 MPa, 20.8% and 58.7%, respectively. The yield strength and elongation for the bi-modal microstructure were slightly lower than those of the equiaxed microstructure. The Widmanstätten microstructure exhibited poor ductility and low yield strength, while the ultimate strength reached 1078 MPa. The dimple fractured mechanism for the equiaxed and bi-modal microstructures proved excellent ductility. The coexistence of dimple and intercrystalline fractured mechanisms for the Widmanstätten microstructure resulted in the poor ductility.

 

اثر عملیات حرارتی بر ریزساختار و خواص مکانیکی فولاد زنگ‌نزن دوپلکس

Effect of heat treatment on microstructure and

mechanical properties of duplex stainless steel

اثر عملیات حرارتی بر ریزساختار و خواص مکانیکی فولاد زنگ‌نزن دوپلکس

ABSTRACT

Present study concerns the effect of deformation and heat treatment on the microstructure and mechanical properties of a duplex stainless steel. While hot rolling causes the coarse distribution of the constituent phases (ferrite and austenite), 50% cold rolling results into the elongated and splintered two — phase structure. Supersaturated ferrite structure established by water quenching from 1300°C results into the strengthening due to the formation of fine dispersed austenite precipitates within ferrite grain after isothermal heat treatment (1000°C, 0.5 hour). Duplex structure consisting of ferrite and austenite in a fine-grained form is obtained after isothermal heat treatment of cold rolled sample. Cold deformed and heat treated steel exhibits best combination of strength and ductility among all the investigated steel samples.

 

راهنمای عملیات حرارتی آلیاژهای غیرآهنی- آلومینیوم و آلیاژهای آن Heat Treaters Guide

Heat Treater's Guide Nonferrous Alloys Wrought Aluminum and Aluminum Alloys

راهنمای عملیات حرارتی آلیاژهای غیرآهنی- آلومینیوم و آلیاژهای آن

ABSTRACT

3003 Aluminum: Microstructures. (a) 3003-0 sheet, annealed. Longitudinal section shows recrystallized grains. Grain elongation indicates rolling direction, but not the crystallographic orientation within each grain. Polarized light. Barker's reagent. 100x. (b) 3003-0 sheet, annealed. Same as adjoining microstructure, but shown at a higher magnification. Dispersion of insoluble particles of (Fe,Mn)Als (large) and aluminum-manganese-silicon (both large and small) was not changed by annealing.

 

راهنمای عملیات حرارتی آلیاژ های منیزیم

Heat Treater's Guide: Mg Alloys
راهنمای عملیات حرارتی آلیاژ های منیزیم

آلیاژ منیزیم ، آلومینیوم، روی

آلیاژ منیزیم، زیر کونیوم

آلیاژ منیزیم، کروم

 AZ91C ،AZ92A،EQ21A،EZ33A،HK31A،HZ32A،AZ91A،AZ91B،AZ91D،AZ91E،AZ81A

ABSTRACT

The principles which govern heat treatment of metals and alloys are applicable to both ferrous and nonferrous alloys. However, in practice there are sufficient differences to make it convenient to emphasize as separate topics the peculiarities of the alloys of each class in their response to heat treatment. For example, in nonferrous alloys, eutectoid transformations, which play such a prominent role in steels, are seldom encountered, so there is less concern with principles associated with time-temperaturetransformation diagrams and with martensite formation. On the other hand, the principles associated with chemical homogenization of cast structures are applicable to many alloys in both classes. Diffusion Process The diffusion process is involved in nearly all heat treatments for nonferrous alloys. Common treatments include:

• Annealing after cold working
• Homogenization of castings
• Precipitation hardening treatments
• Development of two-phase structures

اثر عملیات حرارتی در جوشکاری انفجاری فولاد زنگ نزن/مس

Effect of heat treatment on bonding interface in explosive welded
copper/stainless steel

اثر عملیات حرارتی روی فصل مشترک اتصال در جوشکاری انفجاری فولاد زنگ نزن/مس

ABSTRACT

In this investigation, explosive welding and heat treatment processes provided an effective method for manufacturing high-strength and high-ductility copper/ austenitic stainless steel couple. In order to improve diffusion in the interface of copper/stainless steel, first the tensile samples were provided from the welded part, then they were subjected to annealing at 300 C (below recrystallization temperature) for 8–32 h with 8 h intervals and then samples were cooled in the furnace. Optical microscopy (OM), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were utilized to evaluate the possibility of diffusion in the joints. Moreover, in order to measure the hardness of the samples, microhardness test was performed. Microstructural evaluations showed that the stainless steel 304L had a wavy interface. Furthermore, the post heat treatment process resulted in great enhancement of diffusion. Microhardness measurements showed that the hardness of the sample near to the interface is greatly higher than other parts; this is due to plastic deformation and work hardening of copper and stainless steel 304L in these regions. The interface of samples with and without the post heat treatment was exhibited ductile and brittle fracture, respectively.