INFLUENCE OF EXTRUSION ON DAMPING CAMCITIES OF AS-SPRAY DEPOSITED HIGH SILICON ALLOY ZA27 MODIFIED BY CERIUM

1.IntroductionThedampingcapacityofamaterialreferst0itsabilitytoc0nvertmechanicalvibrationenergyint0thermalenergy.Theapplication0fhighdampingmaterialsmayeliminatetheneedforspeciaienergyabs01bers0rdamperst0attenuateundesirablen0iseandmechan-icalvibrati0n.However,m0st0fthefrequentlyusedmetalsandaJl0ysusuallyexhibitalowdampingcapacity,whicharelimitedintheirapplicati0nandperf0rmanceindynamicstructures[l].Accordingly,materialresearchershavesoughtt0improvethedampingcapacityofmetalsandall0ysasseri0us…     

INFLUENCE OF CERIUM CONTENT ON DAMPING CAPACITIES OF AS-SPRAY DEPOSITED HIGH SILICON ALLOY ZA27

ＩＮＦＬＵＥＮＣＥＯＦＣＥＲＩＵＭＣＯＮＴＥＮＴＯＮＤＡＭＰＩＮＧＣＡＰＡＣＩＴＩＥＳＯＦＡＳＳＰＲＡＹＤＥＰＯＳＩＴＥＤＨＩＧＨＳＩＬＩＣＯＮＡＬＬＯＹＺＡ２７①ＬｉｕＹｏｎｇｃｈａｎｇ，ＬｕＹｉｌｉ，ＹａｎｇＧｅｎｃａｎｇ，ＺｈｕＺｈｅｎｇａｎ...     

INFLUENCE OF ZIRCONIUM ON MICROSTRUCTURE AND DAMPING CAPACITY OF ZA27 ALLOY

1.IlltroductionThedampingcapacityofamaterialreferstotheabilitytoconvertmechanicalenergyofvibrationintoheatthatisdissipatedinthematerial.Itisofgreatsignificancetoimproveitbecausethehighdampingmaterialcanattenuateundesirablenoiseandvibrationandremovethemtothesurroundingsll,2].Itiswellknownforsometimethatcertainzincaluminumajloysfallintothecategoryofhigh-dampingalloys(HIDALLOYS)['].TheZA27ajloyhashighas-caststrength,hardness,andwearresistanceaswellasotherfavorablephysicalproperties.Itisalmos…     

均匀化处理对ZA35-0.3Zr合金组织及性能的影响

为了探索均匀化处理对ZA35-0.3Zr合金组织和性能的影响规律,通过组织分析、力学性能、电化学性能测试,确定了ZA35-0.3Zr合金均匀化处理的适宜温度和时间。结果表明,ZA35-0.3Zr合金枝晶偏析明显,晶界上Cu富集严重,存在非平衡β相。随着均匀化处理时间增加,ZA35-0.3Zr合金中CuZn5相逐渐消除,β相共析分解程度加大。对合金进行370℃×12h均匀化处理后,晶界处CuZn5相消除,枝晶偏析大大减少,同时非平衡β相基本消除,抗拉强度为306MPa,伸长率为7.35%。在3.5%的NaCl溶液中,开路电位与未均匀化处理合金相比变正,腐蚀电流密度减小了33.1%,耐腐蚀性增强。ZA35-0.3Zr合金适宜的均匀化处理工艺为370℃×12h。     

DAMPING BEHAVIOR OF ULTRAFINE-GRAINED PURE ALUMINUM L2 AND THE DAMPING MECHANISM

Ultrafine-grained pure aluminum L2 with a mean grain size of 1.0μm was produced by equal channel angular pressing (ECAP) and annealing at 150℃ for 2h. Damping behavior of the alloy was measured using a dynamic mechanical thermal analyzer. The alloy had an excellent damping capacity Q-1 with the ambient value being 9.8×10-3 at 1.0Hz when the strain amplitude was 2.0×10-3. The damping behavior of the alloy showed a non-linear damping variation tendency, that is, with an increase in temperature and a decrease of frequency, the damping capacity of the alloy increased. The damping capacity increased with the strain amplitude when the strain amplitude was less than 4.6×10-5. When the strain amplitude was higher than 4.6×10-5, the damping capacity became a constant and independent of strain amplitude. The high damping capacity was attributed to dislocation unpinning and a drag of dislocation on pinning points.     

Influences of heat treatment on electrochemical characteristics of La0.75Mg0.25Ni2.8Co0.5 hydrogen storage electrode alloy

1　ＩＮＴＲＯＤＵＣＴＩＯＮＤｕｒｉｎｇｔｈｅｌａｓｔｄｅｃａｄｅ ,ｔｈｅｄｅｍａｎｄｆｏｒｔｈｅｎｉｃｋｅｌ/ｍｅｔａｌ ｈｙｄｒｉｄｅ (Ｎｉ/ＭＨ )ｓｅｃｏｎｄａｒｙｂａｔｔｅｒｉｅｓｈａｓｂｅｅｎｇｒｏｗｉｎｇｒａｐｉｄｌｙｂｅｃａｕｓｅｏｆｔｈｅｉｒｈｉｇｈｅｎｅｒｇｙｄｅｎｓｉｔｙ ,ｈｉｇｈＨＲＤ ,ｌｏｎｇｃｈａｒｇｅ ｄｉｓｃｈａｒｇｅｃｙｃｌｅｌｉｆｅａｎｄｆｒｉｅｎｄｌｙｅｎｖｉ ｒｏｎｍｅｎｔａｌｐｒｏｐｅｒｔｉｅｓ[14 ] .Ｈｙｄｒｏｇｅｎｓｔｏｒａｇｅａｌｌｏｙｓ ,ａｓｔｈｅｎｅｇ…     

退火对AlCoCrFeMnTi高熵合金相组成与显微形貌的影响

为了研究退火温度对AlCoCrFeMnTi高熵合金的物相结构、显微组织及硬度的影响,分别采用X射线衍射仪、光学显微镜、扫描电镜和显微硬度计对不同退火温度下AlCoCrFeMnTi合金进行了测试。结果表明:铸态AlCoCrFeMnTi高熵合金物相结构是由bcc主相和fcc相双相组成,且其各相衍射峰普遍较宽,这是由于原子半径差较大和冷却速度快引起的晶格畸变所致。600 ℃退火后,合金中形成了新的hcp相,当退火温度为800 ℃和1000 ℃时,合金衍射峰的峰形并未再发生显著变化。铸态和退火后的AlCoCrFeMnTi合金均为典型的树枝晶结构,1000 ℃退火后的扫描电镜照片中发现了典型的调幅分解组织。合金硬度值在铸态最大,达到了750 HV0.5,随着退火温度升高硬度逐步降低。在经过1000 ℃退火后,一方面由于合金中出现调幅分解组织,使得过饱和的原子大量析出,降低了晶格畸变程度,导致硬度下降;另一方面,由于退火温度的升高,加速了原子的扩散能力,降低了合金内部的内应力,此时合金硬度下降到604.9 HV0.5。     

微合金化元素Zr对5083铝合金组织和性能的影响

在实验室中用井式坩埚炉熔炼铸造了5083和5083+0.1Zr两种铝合金,轧制后在100～450℃范围内退火。通过金相显微镜、显微硬度计、扫描电镜、电子万能试验机、透射电镜对合金的铸态组织、板材纤维组织、力学性能、耐蚀性能、第二相粒子成分进行了分析,研究了微量元素Zr对5083铝合金组织性能的影响。结果表明,添加微量元素Zr能够细化合金组织,与未添加Zr相比,添加0.1Zr的5083合金的铸态晶粒尺寸从123μm降至73μm,并使第二相粒子Al₆Mn(Fe)尺寸变小;同时使晶间腐蚀坑变小,合金耐蚀性得到提高。添加微量元素Zr还能抑制合金板材再结晶,300℃退火1 h无明显再结晶现象;尤其是5083+0.1Zr合金经250℃退火1 h,抗拉强度为389.50 MPa,屈服强度为215.62 MPa,伸长率为18.2%,仍完全满足使用要求。     

ZA16变形锌合金的热稳定性和组织演化

采用热分析方法,研究丁挤压变形ZA16合金不同加工状态下共析转变的表观激活能.结合热处理技术,研究了变形ZA16合金的热稳定性与组织演化的关系.随加工量的增加,材料的激活能降低,热稳定性变弱.铸态合金退火后的硬度降低,而变形合金退火后的硬度明显升高.合金变形过程中呈现的加工软化、退火硬化的现象,是由于加工过程导致了粗晶的碎化,使得材料能够容许更大的变形量.退火后沿加工方向的析出组织,破坏了发生协调变形所需的球化组织在受力过程中的晶粒转动,导致退火硬化现象的发生.     

Effects of Ce on damping capacity of AZ91D magnesium alloy

1　INTRODUCTIONThedampingcapacityisameasureoftheenergydissipatedduringmechanicalvibrationinthematerialsorcomponent .Metallicmaterialshavinghighdamp ingcapacitybecomevaluableinsuppressingmechani calvibrationandattenuatingwavepropagationforthecontrolofnoiseandthestabilizationofstructures .Takinghighdampingmetallicmaterialsasstructuralpartscouldeliminatetheneedforspecialenergyab sorbersordamperstoattenuatethevibrationandnoise ,inspiteofmostofthefrequentlyusedmetalsandalloys ,whichexhibitarela…     

Damping behavior and mechanical properties of Mg-Cu-Mn alloy processed by equal channel angular pressing

Equal channel angular pressing(ECAP) was conducted at 250℃for 4 passes to the as-extruded Mg-3%Cu-1%Mn alloy with high strength and high damping capacity.After ECAP processing,the grain of as-extruded alloy is significantly refined to about 4μm,both yield strength and tensile strength of the as-extruded Mg-Cu-Mn alloy are decreased,but the ductility is improved.After the ECAP processing,the damping capacity of Mg-Cu-Mn alloy is decreased at room temperature,while is substantially increased at elevated te...     

Effect of annealing on the microstructures and Vickers hardness at room temperature of intermetallics in Mo-Si system

The microstructures and Vickers hardness at room tempcrature of arc-melting processed intermetallics of Mo5Si3-MoSi2 hypoeutectic alloy and hypereutectic alloy annealed at 1200℃ for different time were investigated. Lamellar structure consisted of MosSi3 (D8m) phase and MoSi2 (C11b) phase was observed in all the alloys. For Mo5Si3-MoSi2 hypoeutectic alloy, the lamellar structure was found only after annealing and developed well with fine spacing on the order of hundred nanometers after annealing at 1200℃ for 48 h. But when the annealing time was up to 96 h, the well-developed lamellar structure was destroyed. For Mo5Si3-MoSi2 hypereutectic alloy, the lamellar structure was found both before and after annealing. However the volume fraction and spacing of the lamellar structure did not change significantly before and after annealing. The effects of the formation, development and destruction of lamellar structure on Vickers hardness of alloys were also investigated. When Mo5Si3-MoSi2 hypoeutectic alloy annealed at 1200℃ for 48 h, the Vickers hardness was improved about 19% compared with that without annealing and formation of lamellar structure. The highest Vickers hardness of Mo5Si3-MoSi2 hypereutectic was increasing about 18% when annealing at 1200℃ for 48 h.     

退火温度对Fe-Cr-Mo合金减振性能及力学性能的影响

采用弯曲共振法测量Fe-Cr-Mo合金的减振性能,通过光学显微镜和扫描电镜对合金组织进行观察,研究了退火温度（900～1100℃）对Fe-Cr-Mo合金减振性能和力学性能的影响。结果表明,Fe-Cr-Mo合金在900～1100℃退火温度范围内,随着退火温度的升高,合金的内耗先升高后降低,在1000℃达到峰值4. 7×10^-3。同时,退火温度对合金的力学性能有明显的影响。900℃退火后,合金的抗拉强度和塑韧性最好,抗拉强度为513 MPa,伸长率为37. 25%,断面收缩率为83%,冲击吸收能量为414 J。1100℃退火后,规定塑性延伸强度最大,为395. 5 MPa。      

退火工艺对含铒5A06铝合金组织性能影响

对含铒5A06铝合金进行75~450℃,1h退火处理和75、150、200、250、275、300、400、470℃的从0.5~100h退火处理,并对退火后的合金进行硬度测试、光学显微镜分析、扫描电镜分析,发现退火温度对合金组织性能影响显著,退火时间对合金影响较微小。进行不同温度1h退火时,在75℃退火,合金硬度少量下降;在125~250℃温度退火,随退火温度增加合金硬度下降趋势较缓,耐腐蚀性普遍较低;在250~275℃退火后,合金硬度大幅下降,降幅达28%,但耐腐蚀性能显著提高;275℃以上温度退火,合金硬度变化趋于稳定。进行不同时间退火时,合金在小于200℃和大于275℃时硬度随时间的变化不明显,合金在任一温度下退火0.5h即可完成主要的组织性能转变,退火100与0.5h的合金组织性能差异不大,但在200~275℃区间内,随退火时间延长合金硬度连续下降,250℃退火时合金硬度随时间的延长下降最为明显。在本实验不同退火工艺下合金硬度HV均不小于850MPa。     

电线电缆用Al-Fe-Cu-0.25La-Zr耐热合金的导电性能

采用导电率测试仪、万能拉伸试验机、光学显微镜等分别测试了Al-Fe-Cu-0.25La-Zr合金的导电率、抗拉强度、伸长率等性能指标及显微组织,研究了电线电缆Al-Fe-Cu-0.25La-Zr合金在不同退火工艺下的导电性能与力学性能。结果表明,合金在350 ℃×2 h退火时达到导电率峰值62.8%IACS,抗拉强度为101.5 MPa,伸长率为32.4%;在300 ℃退火2 h时导电率达到62.1%IACS,抗拉强度为125.0 MPa,伸长率为13.4%。合金在300 ℃×(4~10) h退火期间,合金的导电率维持相对稳定,且高于350 ℃×(4~10) h,说明合金在300 ℃时具有更好的耐热稳定性。Al-Fe-Cu-0.25La-Zr合金最优的退火工艺为300 ℃×2 h,此工艺处理后的合金线材符合对电线电缆电学性能与力学性能的标准要求,且可以降低生产成本。     

退火温度对EB熔炼低成本TC4钛合金宽厚板组织和性能的影响

采用EB炉一次熔炼TC4合金扁锭作为直轧坯料,在4200 mm宽厚板轧机上成功制备出规格46 mm×2650 mm×8700 mm的低成本TC4合金宽厚板,研究了退火温度对低成本TC4合金板材显微组织和力学性能的影响。结果表明:EB熔炼TC4合金扁锭经过两火换向轧制,粗大铸态组织得到充分破碎,热轧态TC4合金板材显微组织中等轴α或条状α含量较高,横纵向室温拉伸性能差异小,横向室温冲击吸收能量小于纵向,横纵向心部强度均高于表层。TC4合金板材经750~900 ℃退火,横纵截面为等轴组织,经950 ℃退火,横纵截面为双态组织,经980 ℃退火,横截面为双态组织,纵截面为魏氏组织。随着退火温度升高,TC4合金板材抗拉强度和规定塑性延伸强度呈下降趋势,伸长率基本不变,室温冲击吸收能量先升高后降低,900 ℃退火后,强度、伸长率和冲击吸收能量达到最佳匹配。     

铸态和退火态A2B7型La—Mg—Ni系合金的电化学研究

为了改善铸态La3MgNi14合金的电化学性能,在0．3MPa氩气气氛下对La3MgNi14合金进行了10h退火处理,退火温度分别为1123,1223和1323K。采用x射线衍射（XRD）、扫描电镜（SEM）和电化学实验研究了合金的微观结构和电化学性能。结果表明,铸态及1123K温度退火后的合金由LaNi5相、（La,Mg）2Ni7相以及少量的LaNi2相组成。1223K温度退火后合金含有LaNis,（La,Mg）2Ni7和（La。Mg）Ni3相。1323K温度退火后合金的主相为LaNi5和（La,Mg）Ni3相。与铸态合金相比,退火后合金组织更加均匀,晶粒长大。随着退火温度的增加,合金的一些电化学性能（如最大放电容量、放电效率、循环稳定性）以及动力学参数（如高倍率放电性能）增强,而电位差和电荷迁移电阻降低。在本研究范围内,为了放电容量和循环稳定性之问的平衡,铸态La3MgNi14合金的适宜退火温度为1323K。     

Effects of annealing treatment on the microstructure and electrochemical properties of low-Co hydrogen storage alloys containing Cu and Fe

The effects of annealing treatment on the microstructure and electrochemical properties of low-Co LaNi3.55Mno.35Co0.20Al0.20Cuo.75Fe0.10 hydrogen storage alloys were investigated.X-ray diffraction (XRD) analysis indicated that annealing treatment remarkably reduced the lattice strain and defects,and increased the unit-cell volume.The optical microscope analysis showed that the as-cast alloy had a crass dendrite microstructure with noticeable composition segregation,which gradually disappeared with increasing annealing temperature,and the microstructure changed to an equiaxed structure after annealing the alloy at 1233 K.The electrochemical tests indicated that the annealed alloys demonstrated much better cycling stability compared with the as-cast one.The capacity retention at the 100th cycle increased from 90.0％(as-cast) to 94.7％ (1273 K).The annealing treatment also improved the discharge capacity.However,the high rate dischargeability (HRD)value of the annealed alloy slightly dropped,which was believed to be ascribed to the decreased exchange current density and the hydrogen diffusion coefficient in alloy bulk.     

退火工艺对Ti-4Al-2V合金组织及耐蚀性能的影响

对挤压成形Ti-4Al-2V合金棒材进行普通退火、再结晶退火、双重退火处理,并通过X射线衍射仪、扫描电镜对退火前后的组织结构进行表征。同时,通过电化学工作站测试钛合金在3.5％NaCl溶液中的耐腐蚀性能,分析热处理工艺与合金腐蚀倾向间的相关性。结果表明,未处理合金棒材表面无明显宏微观缺陷,不同温度退火后钛合金主要组织为α相,960 ℃+570 ℃双重退火后,合金组织由粗晶粒状的α相和细针状的α相组成。未处理合金伴有网篮组织,经不同温度退火后获得少量魏氏组织和双态组织。通过分析不同温度退火后钛合金的极化曲线与交流阻抗谱可知,相比未处理合金,760 ℃退火后合金的自腐蚀电流密度较小,对应的极化电阻较大,腐蚀倾向较小,960 ℃+570 ℃双重退火后合金的Nyquist图显示最大的容抗弧,表明其耐蚀性能较好。     

喷雾沉积Ce变质高硅ZA27合金组织与性能

研究了０５％Ｃｅ变质前后喷雾沉积高硅ＺＡ２７合金的组织与力学性能。喷雾沉积高硅ＺＡ２７合金的组织由富Ｓｉ相、光滑无特征区、细层片状共析体、粗层片状共析体所组成；加０５％Ｃｅ变质后，组织结构大大细化，主要由富Ａｌ、Ｃｅ亮点状相、富Ｓｉ、Ｃｅ多角形相以及细层片状共析体组成；显微硬度测量结果表明，Ｃｅ变质提高了材料的塑性，从而有利于高硅ＺＡ２７合金的推广应用。