20 June 2020, Volume 44 Issue 6

    

• Select all
  |

• Select
  Research Progress on Sn-Zn Solder

  XU Kaikai, ZHANG Liang, SUN Lei, XIONG Mingyue, ZHAO Meng, JIANG Nan

  Materials For Mechanical Engineering. 2020, 44(6): 1-5,32. https://doi.org/10.11973/jxgccl202006001

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  A new Sn-Zn lead-free solder is non-toxic, inexpensive, and has a similar melting point to Sn-Pb solder, which makes it one of the most likely material to replace traditional Sn-Pb solder. On the basis of research results of Sn-Zn system lead-free solder at home and abroad, the effects of the addition of alloying elements on the wettability, oxidation resistance, mechanical properties, microstructure and interface structure of the solder are summarized, and future research direction is put forward.
• Select
  Research Progress on Preparation and Toughening Mechanisms ofCarbide Laminar Ceramics

  SHI Xiumei, ZHANG Lijun, ZHENG Yangsheng, CHENG Yingye, WANG Qiang, ZHANG Le, ZHENG Shunqi, SHI Geping

  Materials For Mechanical Engineering. 2020, 44(6): 6-9,15. https://doi.org/10.11973/jxgccl202006002

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  Laminated structures designed by bionics principle can better solve intrinsic brittleness problems of carbide ceramics. It is now one of the most effective ways to strengthen and toughen carbide ceramics, and has good application prospects. The structural design features of laminar ceramics are described. The preparation, performance and main toughening mechanisms of SiC and B₄C laminar ceramics are reviewed. The development of carbide laminar ceramic materials is summarized and prospected.
• Select
  Corrosion Behavior of B₄C/6061Al Composite for Neution Absorption in Boric Acid Solution

  LI Ning, ZHENG Yue, HAN Yu, WANG Yuxin, WU Ming, WANG Quanzhao

  Materials For Mechanical Engineering. 2020, 44(6): 10-15. https://doi.org/10.11973/jxgccl202006003

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  General corrosion, crevice corrosion and encapsulated corrosion behavior in boric acid solution (90 ℃) of the B₄C/6061Al composite material by pickling, anodizing, shot peening treatment, respectively, was studied. The results show that the pickling, anodizing, and shot peening treated specimens had little change in quality, thickness, and density after corrosion for different times. After general corrosion, the anodizing and shot peening treated specimens showed no obvious corrosion traces, while the color of pickling treated specimen surface became darker with increasing corrosion time. After crevice corrosion, the surface of the non-simulated crevice corrosion area of the specimen was in good condition, while the corrosion of the simulated crevice corrosion area was relatively serious. After encapsulated corrosion, local corrosion occurred on the specimen, flocculent aluminum oxides were generated, and anodized film of the anodizing treated specimen was partially peeled off.
• Select
  Effect of SO₃^2- Concentration on Corrosion Behavior of 5052 AluminumAlloy in Alternating Electric Field with Cyclic Wet-Dry Condition

  LIN Yinrong, LIN Tianshun, ZHUANG Jianhuang, SHAO Yanqun

  Materials For Mechanical Engineering. 2020, 44(6): 16-20,24. https://doi.org/10.11973/jxgccl202006004

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  The corrosive solution containing chlorine with pH 4.0 and 400 kV·m^-1 alternating electric field were used to simulate the industrial transmission environment. The effect of SO₃^2- concentration (0.005,0.010,0.020,0.050,0.100 mol·L^-1) on corrosion behavior of 5052 aluminum alloy in alternating electric field with cyclic wet-dry condition was studied. The results show that with the increase of SO₃^2- concentration, the corrosion mass increment, free-corrosion potential, solution resistance, and charge transfer resistance of 5052 aluminum alloy increased first and then decreased, while the free-corrosion current density and corrosion rate decreased first and then increased. When the concentration of SO₃^2- was from 0.005 to 0.020 mol·L^-1, the main corrosion was the pitting corrosion, and cracked corrosion products of Al₂O₃ and Al₂O₃·3H₂O began to appear in pitting pits. When the concentration of SO₃^2- continued to increase, the corrosion pits on the surface of the alloy were reduced, and the cracked corrosion products being tightly bound to the substrate with composition of Al₂O₃ · 3H₂O were increased. The corrosion rate and degree of the alloy were both the smallest when the concentration of SO₃^2- was 0.020 mol·L^-1.
• Select
  Femtosecond Laser Removal Threshold of GH4099 Alloy

  LIU Haijian, CHEN Xu, MA Zhenwu, CHEN Feng

  Materials For Mechanical Engineering. 2020, 44(6): 21-24. https://doi.org/10.11973/jxgccl202006005

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  Surface material removal processing of GH4099 alloy plate was carried out by 500 fs femtosecond laser, and the effect of laser power on the morphology, micro-component and diameter of the material removal region was studied. The laser power and removal area diamenter was linearly fitted by least square method, and the removal threshold of the alloy was determined. The results show that when the laser power was not higher than 1.911 3 W, GH4099 alloy showed one removal area A having the same morphology and composition as the substrate, when the laser power was higher than 1.911 3 W, area B having melting-solidification morphology was present in the center of area A, and had more C and O elements than the substrate. The material removal forms of areas A and B were electrostatic stripping and thermal evaporation, and the laser removal thresholds were 0.413, 12.9 J·cm^-2, respectively. The reasonable laser energy density of laser processing of GH4099 alloy was 0.413-12.9 J·cm^-2.
• Select
  Effect of Stress Ratio on Fatigue Crack Growth Rate of ST12 Low Carbon Steel

  LIU Hu, GONG Yu, ZHANG Chao, KANG Hongbin

  Materials For Mechanical Engineering. 2020, 44(6): 25-27,32. https://doi.org/10.11973/jxgccl202006006

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  Fatigue crack growth rates of ST12 low carbon steel plate under different stress ratios (R=0.2, -0.3,-1) were tested, the crack growth rate curve characterized by the effective stress intensity factor range was obtained by Newman crack closure model. The results show that the crack growth rate of ST12 low carbon steel plate under different stress ratios increased with the crack length. When the stress intensity factor range was constant, the crack growth rate increased with the stress ratio. The stress intensity factor range at fracture of ST12 low carbon steel decreased with increasing stress ratio. The crack growth curves under different stress ratios agreed well with each other when characterized by the effective stress intensity factor range, and the crack closure was the main reason for the difference in crack growth rates under different stress ratios.
• Select
  Effect of Spark Plasma Sintering Temperature on Microstructure andMechanical Properties of Ti-45Al-6Nb-0.3W Alloy

  YANG Dongye, TIAN Wenqi, LI Jiuxiao, GU Xu, LIU Na, ZHANG Guoqing, SUN Jianfei

  Materials For Mechanical Engineering. 2020, 44(6): 28-32. https://doi.org/10.11973/jxgccl202006007

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  Spark plasma sintering of argon atomized Ti-45Al-6Nb-0.3W alloy powders was carried out at different temperatures (1 150, 1 200, 1 250 ℃). The effect of sintering temperature on microstructure and mechanical properties of the alloy was studied. The results show that the spark plasma sintered TiAl alloy consisted of γ and α₂ phases. With increasing sintering temperature, the structure morphology changed from lamellar and equiaxed shape to full lamellar shape, and the grain size and the γ phase content increased. The density of the alloy increased slightly with the sintering temperature, and the hardness changed little. The compression properties of the alloys sintered at different temperatures were better than those of the as-cast alloy. The alloy sintered at 1 200 ℃ showed the best room temperature compression performance with compressive strength of 3 012 MPa and compressibility of 40.8%.
• Select
  Effect of Pre-film Time, Corrosion Temperature and Medium Flow Velocity onCorrosion Inhibition Performance for Oil Well Pipe Inhibitor

  XIE Nanxing, WANG Chuanlei, LI Yufei, ZHANG Lin, SHU Gang, LU Minxu

  Materials For Mechanical Engineering. 2020, 44(6): 33-37. https://doi.org/10.11973/jxgccl202006008

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  P110S tubing steel was pre-filmed with imidazoline corrosion inhibitors, and then the corrosion test was performed. The effects of pre-film time (0.5-4 h), corrosion temperature (30-120 ℃) and medium flow velocity (2-12 m·s^-1) on the corrosion inhibition performance were studied. The results show that with the increase of inhibitor content and pre-film time, the corrosion inhibition rate and the film formation effect on the tubing steel surface increased. The corrosion inhibition performance was relatively good at the inhibitor mass concentration of 300 mg · L^-1and pre-film time of 2 h. With increasing temperature, the inhibitor inhibition rate decreased, the corrosion resistance of the 2 h pre-filmed sample decreased first and showed the worst at 80 ℃; the inhibitor started to fail. The corrosion rate of the 2 h pre-filmed sample increased with the flow velocity. When the medium flow velocity was higher than 10 m·s^-1, the pre-filmed samples were seriously corroded, and the corrosion inhibitor was no longer applicable.
• Select
  Effect of Welding Current on Formability and Microstructure of Plasma Arc Cladding Titanium/Steel Dissimilar Metal Joint with Copper Intermediate Layer

  BIAN Jingru, HOU Juncai, ZHANG Qiumei, HOU Donglin, LI Yapeng, LI Wenhu

  Materials For Mechanical Engineering. 2020, 44(6): 38-42,48. https://doi.org/10.11973/jxgccl202006009

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  Copper layer and TA0 titanium layer were sequentially deposited on the Q235B steel plate by plasma arc cladding. The effect of welding current (85, 90, 95, 100, 105 A) on formability and microstructure of the titanium/steel dissimilar metal welded joint was studied. The results show that this welding process could effectively suppress the formation of brittle phases and welding cracks when the welding current was higher than 90 A. With increasing welding current, the unfused area of the cladding layer decreased and the thickness uniformity increased. The cladding layers had the best formability at welding current of 100 A; the titanium layer, copper layer and steel substrate showed good metallurgical combination; the microstructures of titanium layer and copper layer were fine needle dendrite, columnar dendrite, respectively, and that of the heat-affected zone in steel substrate was fine pearlite + ferrite phase and coarse ferrite phase. At different welding currents, the hardness near the copper/titanium interface was the highest. In this area, the titanium and copper grains were interlaced, and a large number of low brittle intermetallic compounds such as CuTi₂ and CuTi precipitated.
• Select
  Effect of Al₉₀Y₁₀ Amorphous Alloy Refiner on Microstructure and Mechanical Properties of A356 Aluminum Alloy

  GUO Shiwei, XU Wenlong, ZHU Shengli

  Materials For Mechanical Engineering. 2020, 44(6): 43-48. https://doi.org/10.11973/jxgccl202006010

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  Al₉₀Y₁₀ amorphous alloy was added to A356 aluminum alloy melt as refiner to refine the alloy. The effect of refiner mass fraction (0, 0.2%, 0.4%, 0.6%, 0.8%, 1%) on the microstructure and mechanical properties of the aluminum alloy was studied. The results show that with the increase of Al₉₀Y₁₀ refiner content, the secondary dendrite spacing of the A356 aluminum alloy decreased first and then increased, the tensile strength, yield strength, elongation after fracture and hardness increased first and then decreased, and the tensile fracture form changed from quasi-cleavage fracture to quasi-cleavage and micropore aggregation mixed fracture. When the mass fraction of the refiner was 0.6%, the secondary dendrite spacing of the A356 aluminum alloy was 39.68% lower than that of the unrefined alloy, and the alloy showed the best mechanical properties. The yttrium aggregate phase formed after adding Al₉₀Y₁₀ refiner in moderation could reduce the precipitation of brittle phase, hinder the solute exchange between α-Al phase and eutectic silicon phase, thereby refining grains and improving mechanical properties.
• Select
  Effect of Processing Parameters on Relative Density and MechanicalProperties of Selective Laser Melted Biodegradable Pure Zinc

  LI Zhibin, YU Guisheng, WANG Xiaojian, LI Wei

  Materials For Mechanical Engineering. 2020, 44(6): 49-53. https://doi.org/10.11973/jxgccl202006011

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  The pure zinc was manufactured by selective laser melting (SLM) technique,and the effect of laser power and scanning speed on the density and mechanical properties of the pure zinc was studied. The results show that with increasing laser power or decreasing scanning speed, the relative density and hardness of the SLM formed pure zinc increased, and the microstructure was columnar crystals with growth direction parallel to the building direction. The optimal parameters for the SLM formed pure zinc were the laser power of 100 W and scanning speed of 300 mm·s^-1; the relative density of the obtained sample reached 99.86%, the hardness was (44.7 ±1.2) HV, and the elastic modulus, elongation after fracture, tensile strength and yield strength were (48.6±2.4) GPa, (8.9±0.7)%, (95.5±3.3) MPa, (67.1±0.4) MPa, respectively.
• Select
  Effect of Carbon Content and Combined Addition of Aluminum and Boron onAnti-aging Characteristics of Low Carbon Steel

  TANG Wenjie, HE Yutian, MOU Zhanqi

  Materials For Mechanical Engineering. 2020, 44(6): 54-58. https://doi.org/10.11973/jxgccl202006012

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  Thermodynamic equilibrium phase diagram of low carbon steel with different carbon content and combined addition of aluminum and boron was calculated through the Thermo-Calc thermodynamic software. The solid solution and precipitation behaviors of carbon, aluminum, and boron elements in the low carbon steel, as well as the microstructure, mechanical properties and anti-aging properties of the test steel, were studied. The results show that the content of dissolved free carbon atom in the test steel matrix increased with the carbon mass fraction from 0.003% to 0.020%. When the carbon mass fraction increased to 0.053%, the precipitation of cementite in the steel increased and the dissolved free carbon atom decreased. After the combined addition of aluminum and boron in the low carbon steel, the nitrogen atom precipitated in the form of AlN and BN, resulting in the decrease of the dissolved free nitrogen atom. The carbon content and combined addition of aluminum and boron had little effect on the tensile properties of the test steel at room temperature. With increasing carbon content, the grain size of the test steel decreased gradually, and the aging index increased first and then decreased. The test steel showed the worst aging resistance at the carbon mass fraction of 0.020%, and the combined addition of boron and aluminum could improve its aging resistance.
• Select
  Single Shot Peening and Composite Shot Peening for 42CrMoA Steel

  ZHAO Zhiqiang, WANG Genquan, ZHANG Limin, ZHANG Xiaoliang, XU Chunguang, JIANG Chuanhai

  Materials For Mechanical Engineering. 2020, 44(6): 59-61,71. https://doi.org/10.11973/jxgccl202006013

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  42CrMoA high strength steel was strengthened by single shot peening, finishing composite shot peening, and polishing composite shot peening. The surface roughness, fatigue performance, surface residual stress, structure refinement and microhardness of the steel under different shot peening conditions were studied. The results show that shot peening methods had little effect on the maximum residual compressive stress and stress layer depth of 42CrMoA steel. The surface residual compressive stress, surface structure refinement, microhardness and fatigue limit of the steel increased in sequence after single shot peening, finishing composite shot peening, and polishing composite shot peening, while the surface roughness decreased in sequence. Composite shot peening, especially polishing composite shot peening, could reduce the shot peening surface roughness of 42CrMoA steel significantly.
• Select
  Cracking Cause of Reheat Steam Pipe of a Power Plant Boiler

  LIU Kexiu, MA Kuo, FENG Xiaoliang, WANG Lian, LU Zhongming, ZHANG Hui

  Materials For Mechanical Engineering. 2020, 44(6): 62-66. https://doi.org/10.11973/jxgccl202006014

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  It was found that cracking occurred on the inner wall of the socket welding branch outlet in the evacuation pipe and the location near the socket of the header pipe of reheat steam pipe in a power plant boiler during overhaul after service for over 100,000 h. The causes of cracking were analyzed by macro- and micro-morphology observation, chemical composition analysis, mechanical property test, microstructure observation, and micro-component analysis. The results show that the structure design of the evacuation pipe of the reheat steam pipe was unreasonable, leading to the accumulation of a large amount of condensate in the horizontal pipe section in front of the first valve of the evacuation pipe back end. Thermal fatigue cracks initiated at the inner wall of the socket welding branch outlet in evacuation pipe, inner wall at down stream part of the header pipe close to the socket and inner wall of the branch outlet of reheat steam pipe under the combined action of countercurrent condensate and high temperature steam. Under the combined effect of steam pressure, cyclic thermal stress and corrosive carbonate substances, thermal fatigue cracks expanded, eventually resulting in the cracking of the pipe.
• Select
  Fracture Cause of Tie Bar of a Large-Scale Injection Molding Machine

  YU Nahong, CHEN Xu

  Materials For Mechanical Engineering. 2020, 44(6): 67-71. https://doi.org/10.11973/jxgccl202006015

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  The early fracture of the tie bar of a large-scale injection molding machine occurred during service. The fracture cause was studied by fracture morphology observation, chemical composition analysis, non-metallic inclusion analysis, microstructure observation and mechanical property test, and some improvement measures were put forward. The results show that the fracture characteristic of the tie bar was ductile fracture. Under the combined action of thermal stress, microstructure stress caused by improper subsequent heat treatment and continuous reciprocating tensile force, the cracks initiated from the stress concentration of shrinkage cavity residue and banded segregation in the core, and propagated, finally leading to the fracture of the tie bar. After strictly controlling the chemical composition of raw materials, properly increasing the normalizing temperature, increasing the forging ratio, properly prolonging the preheating holding time, and properly prolonging the quenching holding time, such failure did not happen again.
• Select
  High-Resolution Characterization of Microstructural Damage inMaterials by Synchrotron Radiation Source 4D In-situ Tomography

  WU Shengchuan, WU Zhengkai, HU Yanan, BAO Jianguang, LI Fei, XIAO Tiqiao, YUAN Qingxi

  Materials For Mechanical Engineering. 2020, 44(6): 72-76. https://doi.org/10.11973/jxgccl202006016

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  Synchrotron radiation source with high spatial and temporal resolution is a large-scale scientific instrument representing kernel creativity of modern fundamental sciences. Research progress on in-situ loading machines based on high-energy X-ray 3D tomography is described. A set of in-situ loading rigs independently developed by the author team on the basis of Shanghai synchrotron radiation source and Beijing synchrotron radiation facility since 2011, including in-situ tensile, compression, low-cycle fatigue, high-cycle fatigue and super high-cycle fatigue testing machine as well as the sample environment, and researches on high-strength lightweight materials (such as laser welded aluminum alloy and additively manufactured aluminum and titanium alloys) are concisely discussed. The results show that in-situ loading machines play a key role in characterizing microstructural damage evolution of advanced materials, and also are the major supporting of large-scale scientific instruments related to national competitiveness.
• Select
  Research and Application of Macro Fiber Composite and Actuator

  ZHANG Xuewu, ZENG Tao, ZHAO Cheng, SHI Xiumei, JIANG Chunyan

  Materials For Mechanical Engineering. 2020, 44(6): 77-81. https://doi.org/10.11973/jxgccl202006017

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  Macro fiber composite (MFC for short) is a new type of piezoelectric fiber composite material. Devices made of MFC are both sensors and actuators. With a d₃₃ mode MFC actuator as an example, the piezoelectric constitutive equation of MFC is given. Advantages and disadvantages of three methods for preparing piezoelectric fiber sheets are summarized and compared. Finally, the current status of MFC application is illustrated by listing the actual application cases of MFC actuator in different fields. The application and development prospect of MFC is presented.
• Select
  Research Progress on Piezoelectric Materials in the Field of Energy Harvesting

  LIU Ting, ZHAO Cheng, ZHANG Ganghua, WANG Yuanyuan

  Materials For Mechanical Engineering. 2020, 44(6): 82-87,92. https://doi.org/10.11973/jxgccl202006018

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  Research progress on four piezoelectric application materials in the field of energy harvesting, including piezoelectric ceramics, multi-stacked piezoelectric ceramics, piezoelectric polymers and piezoelectric composites, is reviewed. The structural characteristics, preparation methods, and application occasions are highlighted, and the research trends of the piezoelectric materials in future is proposed.
• Select
  Development of Three Matching Layer Broadband Medical Ultrasonic Phased Array Transducer with 2-2 Piezoelectric Ceramic Composite

  ZHANG Hao, ZHAO Cheng, SHI Xiumei, ZENG Tao

  Materials For Mechanical Engineering. 2020, 44(6): 88-92. https://doi.org/10.11973/jxgccl202006019

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  A three matching layer structure broadband medical phased array transducer was developed with 2-2 piezoelectric ceramic composite by three matching layer design scheme and KLM model optimization method. According to the design parameters, the medical phased array transducer was actually manufactured. The results show that the center frequency of actually produced medical phased array transducer was 2.95 MHz, and the relative bandwidth at -6 dB was about 83.2%, which were basically consistent with the theoretical design results (3.05 MHz, 87.8%) and met the design requirements. The transducer is expected to be used for imaging diagnosis of heart diseases.
• Select
  Piezoelectric Sensor Measurement Principles and Research Progress onSensitive Element Materials

  ZHAO Cheng, JIANG Chunyan, ZHANG Xuewu, SHI Xiumei

  Materials For Mechanical Engineering. 2020, 44(6): 93-98. https://doi.org/10.11973/jxgccl202006020

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  With the continuous development of intelligent society, piezoelectric sensors are increasingly used. The types, structures, measurement principles and application scenarios of piezoelectric sensors are described. The research progress on sensitive element materials is reviewed, and the application of high-temperature piezoelectric materials and lead-free piezoelectric materials is summarized. Finally, the future development direction of piezoelectric sensors is prospected.