Key Laboratory for Material Structure and Strength of Guizhou Province

Guiyang, China

Key Laboratory for Material Structure and Strength of Guizhou Province

Guiyang, China
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Zhou S.,Guizhou University | Liu Q.,Guizhou University | Liu Q.,Key Laboratory for Material Structure and Strength of Guizhou province | Xu P.,Guizhou University | And 2 more authors.
Ferroelectrics | Year: 2017

To get excellent electrical properties of lead-free piezoelectric ceramic (Ba0.85Ca0.15)(Zr0.08Ti0.9Sn0.02)O3 [BCZTS], Bi2O3 was doped to modify BCZTS. The microstructure, phases and electrical properties were investigated by XRD, SEM and ferroelectric test instrument, respectively. The experimental results indicate that the ceramics have pure perovskite structure with 0–0.08 wt.% Bi2O3, indicating that the Bi2O3 diffused into the lattice of BCZTS. And when the content of Bi2O3 reaches to 0.06 wt.%, homogenous microstructure and no pores can be found in ceramic. The ceramic has optimized properties of d33 = 430 pC/N, kp = 49.1%, ϵr = 3998, tan δ = 1.3%. Furthermore, the Curie temperature (Tc) increases firstly and then decreases as increasing the doping amount of Bi2O3. The P-E loops for the ceramics are observed and the value of Pr and Ec is 8.08uC/cm2 and 3.45 kV/cm under 35 kV/cm, respectively. © 2017 Taylor & Francis Group, LLC.


Cai E.,Guizhou University | Liu Q.,Guizhou University | Liu Q.,Key Laboratory for Material Structure and Strength of Guizhou Province | Zhou S.,Guizhou University | And 2 more authors.
Journal of Alloys and Compounds | Year: 2017

Lead free solid solution ceramics (1-x)(Ba0.85Ca0.15)(Ti0.93Zr0.07)O3 - x(Bi0.5K0.5)TiO3 [(1-x)BCZT–xBKT, x = 0, 0.02, 0.04, 0.06, 0.08 mol%] were fabricated by the traditional solid-state reaction technique. The crystalline phase was confirmed by X-ray diffraction (XRD) patterns and Raman spectra, the results show that a pure ABO3 perovskite structure was obtained in all of these samples, suggesting that BKT diffused into BCZT to form a solid solution. The microstructure and crystal structure were investigated by thermal field emission scanning electron microscopy (TFESEM) and field emission transmission electron microscopy (FETEM) respectively. The results show that all of these samples exhibited relatively higher density structure. Monocrystal and polycrystal coexistence structure was obtained in BKT doped ceramics at room temperature. In addition, the piezoelectric, dielectric and ferroelectric properties were systematically studied. The ceramic with x = 0.04 mol% BKT demonstrates good properties: d33 = 162 pC/N, Tc = 103.1 °C, kp = 46.2%, εr = 2,390, tanδ = 1.5%, Pr = 9.33 μC/cm2, Ec = 0.80 kV/mm. © 2017 Elsevier B.V.


Yi Y.,Guizhou University | Yi Y.,Key Laboratory for Material Structure and Strength of Guizhou Province | Liang Y.,Guizhou University | Liang Y.,Key Laboratory for Material Structure and Strength of Guizhou Province | And 4 more authors.
Jinshu Rechuli/Heat Treatment of Metals | Year: 2014

Microstructure, mechanical properties and fatigue life of CL60 wheel steel were studied after heating at 830°C for 30 min and cooling in water for 3-5 s, then tempering at 500°C for 40 min and air-cooling to room temperature. Effect of inclusions and residual stress on fatigue life of the steel was analyzed. The results show that the microstructure is fine sorbite, and the strength and plasticity are improved after the heat treatment. When radial load (F) over 1500 N, with the value of F increasing, contact fatigue life decreases geometrically. Moreover, alumina inclusions will decrease contact fatigue life of the steel, while the effect of sulfide on contact fatigue life is less. After heat treating, the values of residual compression stress increase that prolong the contact fatigue life of the steel.


An X.,Guizhou University | Liu Q.,Guizhou University | Liu Q.,Key Laboratory for Material Structure and Strength of Guizhou Province | Zheng B.,Guizhou University
Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering | Year: 2014

To obtain high performance coating materials, the HEAs MoFeCrTiWAlxSiy coating was prepared on 45# steel by laser cladding. By means of OM, XRD and micro -hardness tester, the microstructure and properties of the high -entropy alloy layer with adding Al and Si element were investigated. The experimental results indicate that the addition of Si element will promote the formation of intermetallic compound, and Al in the coating exhibits obvious the grain refining. In addition, the hardness of the coating is significantly increased, and reaches a maximum (839.3 HV). Adding Al can inhibit the formation of intermetallic compound and induces the simple BCC phase structure of the coating, but the hardness of the coating decrease. Simultaneous addition of Si and Al, the excellent quality coating with detailed microstructure and relatively high hardness can be obtained.


Du P.,Guizhou University | Du P.,Key Laboratory for Material Structure and Strength of Guizhou Province | Liang Y.,Guizhou University | Liang Y.,Key Laboratory for Material Structure and Strength of Guizhou Province | And 6 more authors.
Jinshu Rechuli/Heat Treatment of Metals | Year: 2016

Fracture cause of the classIspring used in HXD3B locomotive was investigated by means of chemical composition analysis, metallographic analysis, hardness test, residual stress test by X-ray diffraction and fracture observation by scanning election microscopy. The results show that there exists mixed grain size and a severe decarburization phenomenon on surface of the spring, when the external stress is excessive, fatigue crack source initiates from inclusions and finally results in fatigue fracture of the spring. © 2016, Editorial Office of "Jinshu Rechuli". All right reserved.


Yi Y.-L.,Guizhou University | Yi Y.-L.,Key Laboratory for Material Structure and Strength of Guizhou Province | Liang Y.-L.,Guizhou University | Liang Y.-L.,Key Laboratory for Material Structure and Strength of Guizhou Province | And 2 more authors.
Cailiao Rechuli Xuebao/Transactions of Materials and Heat Treatment | Year: 2014

Heat treatment of specimen was performed and the transformation temperature was measured by using DIL805A/D differential diameter. Phase structure factor was calculated by the empirical electron theory of solids and molecules (EET). Microstructure, substructure and residual austenite were observed by metallurgical microscope, transmission electron microscope and AMI-21 austenite measuring instrument, respectively. The effect of RE on dynamic transition of GDL-1 steel under air-cooled was investigated. Experimental results show that after adding a certain amount of rare earths, τ/t〈1, and nuclear embryo has not be merged by lateral migration steps, and grow up in the form of sympathetic nucleation to form bainite multi-level fine substructure. RE addition makes Fe-C-RE segregation structural unit of GDL-1 steel increase and the values of phase structure factor (nA, FCD) increase. Under this condition, the resistance of Fe-C-RE segregation unit on phase transformation is increased, the forming of granular bainite is inhibited and bainite ferrite microstructure and substructure are finer. Beside this, RE makes the content and stability of residual austenite increase. ©, 2014, Editorial Office of Transactions of Materials and Heat Treatment. All right reserved.


Zhu Y.,Guizhou University | Liu Q.,Guizhou University | Liu Q.,Key Laboratory for Material Structure and Strength of Guizhou Province | Jiang H.,Guizhou University | Xu P.,Guizhou University
Xiyou Jinshu/Chinese Journal of Rare Metals | Year: 2016

β-tricalcium phosphate (β-TCP) and hydroxyapatite (HA) are regarded as a kind of biological materials. β-TCP and HA calcium phosphate coatings were prepared on the surface of titanium alloy (Ti6Al4V) by laser cladding technology. The bonding interface, phases and surface morphology of the coating were respectively characterized by optical microscope (OM), X-ray diffraction (XRD) and scanning electronic microscope (SEM). The results showed that an excellent bonding between the ceramic layer and the substrate was ensued by a strong chemical and metallurgical interface. The cladding samples consisted of four parts that were substrate, heat-affected zone, alloyed layer, and ceramic layer region. When the addition of La2O3 reached 0.6%(mass fraction), the coating mainly contained CaTiO3, TiO, β-TCP and HA phases. The surface morphology of the coating was observed by SEM, and the results indicated that the La2O3 contents had a great impact on the coating crack sensitivity. When La2O3 contents was up to 0.6%, the coating surface was smooth with a small amount of holes and cracks, and the hardness value of the coating was HV 1971. © Editorial Office of Chinese Journal of Rare Metals. All right reserved.


An X.,Guizhou University | Liu Q.,Guizhou University | Liu Q.,Key Laboratory for Material Structure and Strength of Guizhou Province
Xiyou Jinshu Cailiao Yu Gongcheng/Rare Metal Materials and Engineering | Year: 2016

High entropy alloy (HEA) SiFeCoCrTi coating was prepared on Q235 steel by laser cladding. Effect of WC particles on the microstructure and properties of high entropy alloy SiFeCoCrTi coating was researched. The microstructure, phase, microhardness and wear resistance were investigated by OM, XRD, SEM, hardness testing and wear testing. The result shows that the microstructure of the HEA SiFeCoCrTi coating is dendrite consisting of bcc phase and intermetallics. After adding WC particle, the grain dendrite coating is formed, and large amounts of intermetallics appear in the coating, such as TiCo3 and Co1.07Fe18.93. The WC particle addition decreases dilution rate of the substrate, and increases the properties of the coating, e.g. the average hardness of the HEA FeSiCrCoMo coating increases by 23%, both of wear rate and friction coefficient decrease, and the wear-resistance improves obviously. © 2016, Science Press. All right reserved.


Lei L.,Guizhou University | Lei L.,Key Laboratory for Material Structure and Strength of Guizhou Province | Liang Y.,Guizhou University | Liang Y.,Key Laboratory for Material Structure and Strength of Guizhou Province | And 4 more authors.
Jinshu Rechuli/Heat Treatment of Metals | Year: 2015

The quenching treatment of 20CrNi2Mo steel was carried out with different cooling mediums. The effects of cooling rate on microstructure and mechanical properties of 20CrNi2Mo steel were investigated. The results show that with the increase of cooling rate, the grain size of 20CrNi2Mo steel is almost unchanged, and the martensite lath is refined; the strength increases, the elongation and reduction of area remain unchanged. And with the increase of cooling rate, the impact absorbed energy increases and the fracture changes from brittle to ductile. ©, 2015, Chinese Mechanical Engineering Society of Heat Treatment. All right reserved.


An X.L.,Guizhou University | Liu Q.B.,Key Laboratory for Material Structure and Strength of Guizhou Province | Zheng B.,Guizhou University
Applied Mechanics and Materials | Year: 2014

To obtain the coating with excellent properties, FeWCrMnCoCuTix (x=0.2, 0.4, 0.6) high entropy alloys coating on 45 steel were prepared by laser cladding. By means of OM, XRD and microhardness tester, the effect of Ti content on microstructure and properties of coating is investigated. The experimental result shows that the phase composition of HEAs coating is simple body-centered cubic and face-centered cubic. The microstructure of these alloys is mainly dendrite crystal with grains were fine and uniform. When Ti content increases to x=0.4, the hardness of the coating reaches a maximum (639HV0.2). © (2014) Trans Tech Publications, Switzerland.

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