scholarly journals Optimum heat treatment to enhance the weak-linkresponse of Y123 nanowires prepared by SolutionBlow Spinning

Author(s):  
Ana Maria Caffer ◽  
Davi Chaves ◽  
Alexsander Lourenço Pessoa ◽  
Claudio Luiz Carvalho ◽  
Wilson Aires Ortiz ◽  
...  
2012 ◽  
Vol 13 (1) ◽  
pp. 38-43 ◽  
Author(s):  
Ching-Iuan Su ◽  
Zong-Ying Jiang ◽  
Ching-Hsiang Lu

2012 ◽  
Vol 192-193 ◽  
pp. 556-561 ◽  
Author(s):  
Qiang Zhu ◽  
Stephen Midson ◽  
Chang Wei Ming ◽  
Helen V. Atkinson

Commercial semi-solid cast impellers are produced from Al-Si-Cu alloys heat treated to the T6 temper. The study described in this paper involved the identification of casting and heat treatment parameters to produce semi-solid processed turbocharger impellers from a silicon-free, higher strength 201 alloy. Casting parameters were identified which minimized hot tearing in the alloy 201 impellers. A series of heat treatment studies were performed to determine optimum heat treatment parameters. The T71 temper was identified as the preferred heat treatment condition to produce high strength as well as superior elongation. The results from mechanical property measurements conducted on the T71 heat treated impellers are reported. Optical and scanning electron microscopy (SEM) were also used to characterize the microstructure of alloy 201 impellers before and after heat treatment, and representative microstructures are presented.


2014 ◽  
Vol 1061-1062 ◽  
pp. 454-459
Author(s):  
An Min Li ◽  
Ding Ma ◽  
Qi Feng Zheng ◽  
Ruo Huai Chen ◽  
Qiang Li ◽  
...  

The as-cast grate bar structure used in sintering trolley is primarily comprised of austenite and eutectic (eutectic austenite and eutectic carbide).The austenite is dendrite, while the carbides are reticular and chrysanthemum-like. The failed grate bar structure primarily consists of ferrite, carbide, martensite and residual austenite; cavity shrinkage and shrinkage porosity exist in the structure, and the fracture exhibits typical cleavage fracture characteristics. The primary means of failure are abrasion and fracture. The secondary carbides precipitated in the sample (quenching (1050°C+2.5h)+ tempering (390°C+2.5h)) and the other one (quenching (1050°C+2.5h)+ tempering (420°C+2.5h) ) are dispersed and refined. Compared with the as-cast one, their relative abrasion resistance performances respectively are 0.8645 and 0.8752.The values of hardness and impact toughness of the samples heat-treated are greater than those of the as-cast grate bar. The optimum heat treatment process is as follows: quenching (1050°C,2.5h) + tempering (390°C~420°C,2.5h)


Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1271
Author(s):  
Tingwei Ma ◽  
Xianchao Hao ◽  
Ping Wang

In this study, the phase transformation temperature of 15Cr12MoVWN ferritic/martensitic steel was determined by differential scanning calorimetry to provide a theoretical basis for the design of a heat treatment process. An orthogonal design experiment was performed to investigate the relationship between microstructure and heat treatment parameters, i.e., normalizing temperature, cooling method and tempering temperature by evaluating the room-temperature and elevated-temperature tensile properties, and the optimum heat treatment parameters were determined. It is shown that the optimized heat treatment process was composed of normalizing at 1050 °C followed by air cooling to room temperature and tempering at 700 °C. Under the optimum heat treatment condition, the room-temperature tensile properties were 1014 MPa (UTS), 810.5 MPa (YS) and 18.8% (elongation), while the values are 577.5 MPa (UTS), 469 MPa (YS) and 39.8% (elongation) tested at 550 °C. The microstructural examination shows that the strengthening contributions from microstructural factors were the martensitic lath width, dislocations, M23C6, MX and grain boundaries of prior austenite grain (PAG) in a descending order. The main factors influencing the tensile strength of 15Cr12MoVWN steel were the martensitic lath width and dislocations.


2021 ◽  
Author(s):  
Fenghong CAO ◽  
Yaohui XU ◽  
Chang CHEN ◽  
Zhaohui QIN ◽  
Chi DENG

The relationship among the microstructure, hardness and electrical conductivity of the as-forged ZYK530 Mg alloy after heat treatment was analyzed and studied using a microscope, X-Ray Diffractometer, eddy current conductivity meter, and Vickers microhardness tester, to explore optimum heat treatment process of ZYK530 Mg alloy. The results show that: with the prolongation of holding time, the electrical conductivity and microhardness show the same change trend, both of which show an oscillatory upward trend, and then decrease in an oscillatory downward trend after reaching the  peak value. There is a linear positive correlation between the conductivity and the hardness, and the fitting results of the conductivity and hardness are in good agreement with the measured results; combined with the actual production, when the heat-treatment is 480 ℃ × 8 h + 220 ℃ × 3 h, the highest hardness is 79.2 HV, the electroconductivity is 36.2%IACS, and the comprehensive performance is the best, which is the best heat treatment process.


2021 ◽  
Author(s):  
Chil-Chyuan Kuo ◽  
Shao-Xuan Qiu ◽  
Xin-Yi Yang

Abstract Metal additive manufacturing (MAM) provides lots of benefits and potentials in manufacturing molds or dies with sophisticated conformal cooling channels. It is known that the conformal cooling technology provides effective cooling to reduce cycle time for increasing productivity. Ordinarily, mold inserts fabricated by general printing procedures will result in coolant leakage in the injection molding process. The yield in the manufacturing of fully dense injection molding tools was limited to the very narrow working widow. In addition, high costs of fully dense injection mold fabricated by MAM constitute the major obstacle to its application in the mold or die industry. In general, the high cost of MAM is approximately 50-70% more expensive than conventional computer numerical control machining. In this study, a low-cost and highly efficient method of reducing coolant leakage for direct metal printed injection mold with cooling channels was proposed. This new method employs general process parameters to manufacture the green injection mold rapidly and then uses optimum heat treatment (HT) procedures to improve microstructure of the green injection mold. The results of this study revealed that optimum HT procedures can prevent coolant leakage and save manufacturing time of the injection mold fabricated by direct metal laser sintering. The evolution mechanisms of microstructure were investigated experimentally. The save in the injection mold manufacture time about 67% can be obtained.


2010 ◽  
Vol 160-162 ◽  
pp. 412-417
Author(s):  
Xiao Song Li ◽  
An Hui Cai ◽  
Hua Chen ◽  
Ji Jie Zeng ◽  
Yong Zhou

The effects of heat treatment on morphology of primary α and hardness of B-refined Al-7 wt% Si alloy are investigated. In addition, the optimum heat treatment procedure is also determined. It is shown that, at 450°C with different holding time from 3h to 12h, morphology of primary α phase is converted from irregular dendrite to granular homogeneous equiaxed grains then to rosette structure. The primary α phase is gradually converted from dendrite into the rosette dendrite and then into particle crystal with increasing of temperature by holding 8h at 300~540°C. One can find fine and uniform distributed particle α phase at 400°C or 450°C. However, the primary α phase has changed into large and irregular shape when the temperature increases up to 450°C. The orthogonal analysis shows that the optimum heat treatment parameters are 540±10°Cand 6h.


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