The Effect of Heat Treatment on Microstructure and Mechanical Properties of Ti-8.5Nb-4.5Ta-13Zr Alloy

2017 ◽  
Vol 899 ◽  
pp. 389-394
Author(s):  
Narayanna Marques Ferreira Mendes ◽  
Marcio W.D. Mendes ◽  
Ana Helena de Almeida Bressiani ◽  
Hidetoshi Takiishi

The effects of the heat treatment on the phase transformations, microstructures and mechanical properties of Ti-8.5Nb-4.5Ta-13Zr alloy were studies in this work. Some of the starting powder were obtained by hydrogenation method and homogenized with metallic tantalum in a high-energy planetary mill. The samples were compacted in a uniaxial and cold isostatic presses and then, sintered at 1150 °C for 10 hours under high vacuum. The heat treatments were carried out at the same sintering temperature, above the α / β transus, at different cooling rates such as furnace cooling, air cooling and water quenching. The sintered samples were characterized using the Archimedes density method, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The microhardness was measured using the Vickers indentation (ASTM E384-11 Standard). It was shown that the microstructure of Ti-8.5Nb-4.5Ta-13Zr alloy consists of beta-phase matrix and alpha-phase region of two structures: equiaxed and needle-like grains also known as Widmanstätten structure. The precipitation of the alpha-phase in the beta-phase matrix led to an increase in Vickers microhardness of the alloy which was furnace cooled. Moreover, a few remaining pores were still found and density above 98% was achieved.

2020 ◽  
Vol 321 ◽  
pp. 08003
Author(s):  
Yujun Du ◽  
Xianghong Liu ◽  
Jinshan Li ◽  
Wenzhong Luo ◽  
Yongsheng He ◽  
...  

Small button ingots of Ti2AlNb alloys with different contents of Mo, V and Zr were melted by vacuum non-consumable arc furnace. Due to the rapid cooling rate during melting process, only β grains without precipitation were observed in most of the button ingots and no regular phenomenon was found. However, when the samples were heated to β phase region and then furnace cooled to room temperate, different morphologies and quantities of primary α phase and second O phase formed from the β grains of different samples. It is suggested that the morphology of α phase was changed from lamellar to quadrilateral with increasing V and the lath O increased with increasing Zr. Besides, the residual β/B2 phase increased with increasing Mo and V. The EDS results showed that Al and Zr were enriched in α phase whereas Nb, Mo and V were enriched in β/B2 phase. The micro-hardness of these samples before and after heat treatment was detected and the micro-hardness increased with increasing Zr and decreasing Mo and V.


Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 575 ◽  
Author(s):  
Alexander Gramlich ◽  
Robin Emmrich ◽  
Wolfgang Bleck

New medium Mn steels for forged components, in combination with a new heat treatment, are presented. This new annealing process implies air-cooling after forging and austenite reversion tempering (AC + ART). This leads to energy saving compared to other heat treatments, like quenching and tempering (Q + T) or quenching and partitioning (Q + P). Furthermore, the temperature control of AC + ART is easy, which increases the applicability to forged products with large diameters. Laboratory melts distinguished by Ti, B, Mo contents have been casted and consecutively forged into semi-finished products. Mechanical properties and microstructure have been characterized for the AC and the AC + ART states. The as forged-state shows YS from 900 MPa to 1000 MPa, UTS from 1350 MPa to 1500 MPa and impact toughness from 15 J to 25 J. Through the formation of nanostructured retained metastable austenite an increase in impact toughness was achieved with values from 80 J to 100 J dependent on the chemical composition.


Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2065
Author(s):  
Fei Liu ◽  
Haidong Zhao ◽  
Runsheng Yang ◽  
Fengzhen Sun

Al–Si–Mg based alloys can provide high strength and ductility to satisfy the increasing demands of thin wall castings for automotive applications. This study has investigated the effects of T6 heat-treatment on the microstructures, the local mechanical properties of alloy phases and the fracture behavior of high vacuum die-cast AlSiMgMn alloys using in-situ scanning electron microscopy (SEM) in combination with nano-indentation testing. The microstructures of the alloys at as-cast and T6 treated conditions were compared and analyzed. It is found that the T6 heat treatment plays different roles in affecting the hardness and the Young’s modulus of alloy phases. This study also found that the T6 heat treatment would influence the failure modes of the alloys. The mechanisms of crack propagation in the as-cast and T6 treated alloys were also analyzed and discussed.


2013 ◽  
Vol 747-748 ◽  
pp. 111-114
Author(s):  
Lin Song ◽  
Xiang Jun Xu ◽  
Jun Pin Lin ◽  
Lai Qi Zhang

Effects of annealing treatment on microstructure and the compressive properties of hot-worked Ti-45Al-8Nb-(W, B, Y) alloy were investigated. Microstructure of the extrusion plus multi-step forging pancake before and after heat treatment was analyzed by SEM and TEM, respectively. The annealing was conducted by holding samples at 1100°C for 2hrs, and followed by air cooling and furnace cooling. The mechanical properties were measured by Instron test machine. The microstructure evolution during compressive deformation was analyzed by TEM. The results showed that after the annealing the microstructure change could not be observed under SEM but can be observed under TEM. Many dislocation clusters were removed by heat treatment. The heat treated samples had similar compression behaviors with the pancake. TEM investigation showed that the numerous twin intersections occured in γ matrix during compression. The twin spaces tended to decrease as the deformation and the intersection increasing.


2010 ◽  
Vol 660-661 ◽  
pp. 176-181
Author(s):  
José Hélio Duvaizem ◽  
Gabriel Souza Galdino ◽  
Ana Helena A. Bressiani ◽  
Rubens Nunes de Faria Jr. ◽  
Hidetoshi Takiishi

The effects of the hydrogenation stage on microstructure and mechanical properties of Ti-13Nb-13Zr alloy produced by powder metallurgy have been studied. Powder alloys have been produced by hydrogenation with 250 MPa or 1 GPa and via high energy planetary ball milling. Samples were isostatically pressed at 200 MPa and sintered at 1150 °C for 7, 10 and 13 hours. Elastic modulus and microhardness were determined using a dynamic mechanical analyzer (DMA) and a Vickers microhardness tester. Density of the samples was measured using a liquid displacement system. Microstructure and phases presents were analyzed employing scanning electron microscopy (SEM). Elastic modulus was 81.3  0.8 and 62.6  0.6 GPa for samples produced by 250 MPa and 1 GPa hydrogenation, respectively when sintered for 7h.


2018 ◽  
Vol 770 ◽  
pp. 45-51
Author(s):  
Carlos Romero ◽  
Fei Yang ◽  
Stiliana Raynova ◽  
Leandro Bolzoni

In this study, Ti-6Al-4V bars were first prepared by extrusion of powder compacts from blended powder mixtures in the beta phase region, then the as-extruded bars were heat-treated following four different conditions: beta quenching and aging (βQA), broken up structure (BUS) treatment, solution treatment and aging (STA) and recrystallization annealing (RA). The effect of the heat treatments on microstructure and mechanical properties was studied using optical microscopy, scanning electron microscopy, and mechanical test to determine which heat-treatment condition has the greatest impact on the mechanical properties of the as-extruded Ti-6Al-4V alloy. The results show that the as-extruded condition has the best balance of strength (1120 MPa of UTS) and ductility (11% of elongation to failure). βQA and STA lead to a slight increase in strength but ductility decreases considerably. After BUS and RA treatments, both strength and ductility are reduced. The relationship between processing, microstructure and properties was studied, and their implications towards fatigue behaviour and fracture toughness were discussed.


2016 ◽  
Vol 863 ◽  
pp. 14-18 ◽  
Author(s):  
Mazyan Yahaya ◽  
Salhana Sahidin@Salehudin ◽  
Maheran Sulaiman ◽  
Nur Hidayatul Nadhirah Elmi Azham Shah ◽  
Muhammad Hussain Ismail

The aim of this study is to evaluate the effect of phase formation to the mechanical strength of Ti-Nb alloy produced by powder metallurgy (PM) process. Niobium (Nb) powder was added to the elemental titanium (Ti) powder by wt%, cold-compacted and sintered at 1200°C. The samples were characterized in term of shape and sizes of the particle, phases present, microstructures and compressive strength. XRD pattern showed that increasing Nb content resulted in increased beta-phases which also evidenced by a greater fraction of light gray-scale image in back-scattered SEM analysis. The alpha phase region almost eliminated in the 35 wt% Nb. The lowest compressive strength was observed in 45 wt% Nb is due to partly crystallized region in the microstructure observed. The alloy containing 35 wt% Nb exhibited better beta-phase structures in the matrix. The Young’s modulus of 13.46±2.44 GPa were obtained from 45 wt% Nb addition in the Ti alloy. All sintered samples are potential candidates for implant applications.


2015 ◽  
Vol 727-728 ◽  
pp. 322-326 ◽  
Author(s):  
Shi Lu Zhao ◽  
Zhen Zhang ◽  
Lian Chong Qu ◽  
Jun Zhang ◽  
Jian Ming Wang ◽  
...  

Effects of heat treatment process of quenching and tempering under different temperature conditions on mechanical properties of X70 grade pipeline steel bends were studied. Brinell hardness, yield strength, tensile strength, elongation and impact absorbing energy of the bends were tested by using hardness tester, cupping machine and impact testing machine, respectively. It shows that the best heat treatment process of the X70 grade pipeline steel bends is quenching at 890 °Cand thermal insulation for 26 min then water cooling followed by tempering at 590 °C and thermal insulation for 60 min then air cooling. Furthermore, the resulting hardness, yield strength, tensile strength, yield ratio, elongation and impact absorbing energy reach HB230, 595 MPa, 725 MPa, 0.82, 28% and 300 J respectively, which has excellent comprehensive mechanical properties.


2017 ◽  
Vol 17 (1) ◽  
pp. 121-126 ◽  
Author(s):  
D. Medyński ◽  
A. Janus ◽  
S. Zaborski

Abstract The paper presents influence of soaking parameters (temperature and time) on structure and mechanical properties of spheroidal graphite nickel-manganese-copper cast iron, containing: 7.2% Ni, 2.6% Mn and 2.4% Cu. Raw castings showed austenitic structure and relatively low hardness (150 HBW) guaranteeing their good machinability. Heat treatment consisted in soaking the castings within 400 to 600°C for 2 to 10 hours followed by air-cooling. In most cases, soaking caused changes in structure and, in consequence, an increase of hardness in comparison to raw castings. The highest hardness and tensile strength was obtained after soaking at 550°C for 6 hours. At the same time, decrease of the parameters related to plasticity of cast iron (elongation and impact strength) was observed. This resulted from the fact that, in these conditions, the largest fraction of fine-acicular ferrite with relatively high hardness (490 HV0.1) was created in the matrix. At lower temperatures and after shorter soaking times, hardness and tensile strength were lower because of smaller degree of austenite transformation. At higher temperatures and after longer soaking times, fine-dispersive ferrite was produced. That resulted in slightly lower material hardness.


2018 ◽  
Vol 913 ◽  
pp. 109-117 ◽  
Author(s):  
Qing Yun Zhao ◽  
Si Rui Cheng ◽  
Li Dong Wang ◽  
Li Min Dong ◽  
Feng Lei Liu

The effects of heat treatment on microstructure and mechanical properties of Ti-38644 alloy were investigated by scanning electron microscope (SEM) and transmission electron microscopy (TEM) as well as uniaxial tensile test. The results show that when the solution temperature is lower than 845°C, the microstructure of Ti-38644 alloy is equiaxed β phase with the grain size of 20μm, and the tensile strength is about 960MPa. As raising solution temperature to 860°C, the grain size of Ti-38644 alloy increases to 100μm and the tensile strength decreased to 870MPa. There are a large number of secondary α phase precipitated from the grain boundaries and within grain of β phase undergoing aging treatment. Secondary α phase coarsens with increasing the aging temperature, leading to the decrease of tensile strength. After solution treatment at 815°C for 1.5h, water quenching plus aging at 520°C for 10h, air cooling, Ti-38644 alloy shows a better mechanical property with the tensile strength 1330MPa, elongation and reduction of area 10% and 45% respectively.


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