合金元素对钢筋耐腐蚀性能和机械性能的影响

通过正交试验，研究了成分为(％)：0．10～0．12C，0～0．78Cr，0．32～0．67Ni，0～0．52Mo，0～0．06V，0．30～0．36Cu低碳高强度钢筋的耐蚀性和力学性能。结果表明，Cr能显著提高钢筋的耐氯盐腐蚀性，含0．53％～0．78％Cr、0．32％～0．35％Ni的钢筋具有良好的耐蚀性；加Mo，V可显著提高钢筋的强度。     

Cr含量对WC基硬质合金组织和性能的影响

在WC基硬质合金生产中，为了提高舍金的耐腐蚀性能，通常的做法是加入Cr、Ni等元素对粘结相进行合金化，然而加入Cr以后对合金性能的影响还没有做系统的研究。该文以WC-10(CoNi)为基础，在粘结剂中加入不同含量的Cr，对合金的力学性能以及耐腐蚀性能做了试验研究。试验结果表明，当粘结相中Cr的添加量为4％时，合金出现个别晶粒的异常长大；当Cr的添加量增加到12％时，合金的组织变得均匀并且晶粒得到明显的细化；粘结剂中加入Cr以后。显著提高了合金的耐腐蚀能力。     

Re对耐腐蚀镍基定向高温合金组织及持久寿命的影响

优化设计了4种不同Re含量的耐腐蚀定向镍基高温合金,含Re分别为0%,1%,2%和3%(质量分数)。对比了不同Re含量合金的铸态枝晶、γ’相形貌及持久性能试样的断口筏排化组织,测试了不同Re含量合金热处理态的980℃/200 MPa持久寿命,研究了Re对耐腐蚀镍基定向合金组织及持久寿命的影响。研究表明:随着Re含量的增加,合金的一次枝晶间距减小;γ’相尺寸减小,立方化程度增加;蠕变试样的筏排组织更加细化、完善与稳定,因此,合金持久寿命提高。     

Ni和Nb元素对Fe-Cr-Mo合金力学和阻尼性能的影响

摘要：采用光学显微镜、扫描电镜、透射电镜、弯曲共振试验机和万能材料试验机等分析了复合添加质量分数0.8%Ni元素和0.1%Nb元素的Fe-Cr-Mo合金组织和析出相的大小、形态,研究了Ni和Nb元素的添加对Fe-Cr-Mo合金力学性能和阻尼性能的影响。结果表明,Ni和Nb元素的加入不但使合金晶粒显著细化,而且有效抑制了富Cr析出物的析出,使析出物明显细化且分布弥散。晶粒和析出物的细化同时提高了合金的强度和塑韧性,尤其是显著地提高了材料的塑性。1000和1100℃退火后,Ni和Nb元素的加入将提高减振合金的矫顽力,降低磁致伸缩系数,使减振合金的阻尼性能降低。900℃退火后,Ni和Nb元素的添加虽然提高了合金的矫顽力,但由于Mo元素的回溶使磁致伸缩系数增大,阻尼性能获得提高。     

铼对定向合金组织和性能的影响

以一种定向合金为基础成分，加入不同含量的Re，采用定向凝固工艺浇注性能试棒，通过SEM研究了含Re合金的微观组织特征及Re在不同相中的分布情况，比较了不同Re含量的室温拉伸和高温持久性能。研究结果表明：通过加入Re可以有效提高合金的室温拉伸屈服强度和高温持久寿命，但室温和高温塑性有所降低。加入Re后合金的铸态组织变化不大：γ γ′共晶相数量随Re含量的增加而略有增多，并且尺寸变小。Re主要分布于γ基体中，在强化相γ′中的分布很少，并通过在γ基体中阻碍位错运动有效提高合金的高温强度。     

Ti含量对U-Ti合金组织和性能的影响

采用真空感应熔炼的方法制备了U-0.5％Ti、U-0.75 ％Ti和U-0.95％Ti合金试样,研究了Ti含量对合金微观组织、室温拉伸性能和耐腐蚀性能的影响.结果 表明:三种成分的U-Ti合金组织均以针状和双凸透镜状马氏体为主,物相组成主要有α'相和U2 Ti相;随着Ti含量的增加,U-Ti合金的晶粒逐渐细化,U2Ti...     

热喷涂WC-MoB-Co金属陶瓷涂层的耐腐蚀性能研究

本文采用团聚烧结法制备了WC-MoB-Co金属陶瓷喷涂粉末,使用超音速火焰喷涂技术在316L不锈钢基材上制备了WC-MoB-Co涂层;采用SEM、XRD表征了WC-MoB-Co粉末和腐蚀前后涂层的微观形貌及物相组成;测试了WC-MoB-Co涂层耐熔融锌铝腐蚀性能。研究结果表明,制备的WC-MoB-Co金属陶瓷复合粉末粒度集中、流动性好、松装密度高;WC-MoB-Co涂层结合强度高、孔隙率低;WC-MoB-Co涂层具有良好的耐腐蚀性能,随着腐蚀时间的延长,涂层中的WC颗粒逐渐参与反应。     

CoCrFeNiCuTix高熵合金的微观组织与耐腐蚀性能研究

采用真空热压烧结法制备了CoCrFeNiCuTi_x (x为摩尔比, x=0.25, 0.50, 0.75, 1.00)六元高熵合金, 研究了Ti含量对该高熵合金微观组织和耐腐蚀性的影响。利用金相显微镜、X射线衍射仪、扫描电子显微镜、HVS-1000B型数显显微硬度计和电化学工作站等设备测试和分析了CoCrFeNiCuTi_x高熵合金的组织结构和耐腐蚀性能。结果表明: 不同Ti含量(摩尔分数)的CoCrFeNiCuTi_x高熵合金, 物相都为面心立方结构, 组织主要为树枝晶; 随着Ti摩尔分数的增加, 高熵合金树枝晶组织减少, 硬度先增加后减小, x=0.50时, 合金的硬度值最大, 为HV 755;CoCrFeNiCuTi_x高熵合金的自腐蚀电位都正于45#钢, 耐腐蚀性先增强后减弱, x=0.50时, 其耐腐蚀性最优。     

Ni元素对Al-Si-Cu基真空钎焊料接头性能的影响

研究了添加Ni的Al-Si-Cu基钎料真空钎焊LF21铝合金接头的力学性能、微观组织形貌.结果表明,采用添加Ni元素的真空钎料,可提高钎焊接头的剪切强度,其机制在于Ni元素能够改善LF21铝合金真空钎焊接头焊缝及其基体组织的分布.但随着Ni元素含量的增加,其钎料的熔点也有所提高.     

氧化锆含量对钼合金组织和性能的影响

采用粉末冶金工艺制备了含不同质量分数氧化锆（ZrO₂）的钼合金棒材,通过拉伸力学性能测试、硬度测试、光学显微镜观察等分析手段,研究了ZrO₂含量对钼合金显微组织和力学性能的影响。结果表明:ZrO₂的添加细化了钼合金晶粒,随着ZrO₂质量分数的增加,钼锆合金的硬度和室温抗拉强度增加。当ZrO₂质量分数为2.5%时,钼锆合金的硬度达到最大值（HV₁₀ 240）,抗拉强度达到最大值（820 MPa）。     

合金元素对316LN不锈钢的力学性能和点蚀性能的影响

研究了N、Cr、Mo和Ni四种合金元素含量的变化对核电主管道用固溶态316LN不锈钢的晶粒尺寸以及常规力学性能和点蚀性能的影响.随着N含量的升高,316LN的晶粒明显细化,其在固溶处理过程中晶粒长大趋势也减小.N含量的升高可改善316LN的力学性能和耐点蚀性能,但是当N质量分数达到0.20%时,其耐点蚀性能又开始变差.晶粒细化对316LN强度的影响远小于N含量对316LN强度的影响.Cr及Ni含量对316LN的晶粒尺寸及抗拉强度、屈服强度等力学性能影响不大;Cr含量增加可轻微改善316LN的抗点蚀能力,Ni元素对316LN的耐点蚀性能影响不大,但可增大钝态的腐蚀速度从而不利于钝化膜的稳定.随Mo含量增加,316LN的晶粒尺寸略有减小,强度增大,延伸率显著降低,耐点蚀能力改善.     

Effect of Nb and Ti on second-phase precipitation and mechanical properties of 430 ferritic stainless steel

The influence of Ti and Nb on the microstructure,mechanical properties,and second-phase precipitation of 430 ferritic stainless steel was investigated.In addition to optical microscopy,transmission electron microscopy and X-ray diffraction analyses,tensile tests,and carbonitride extraction experiments were conducted to investigate the microscopic mechanisms.The results showed that the primary precipitates in SUS 430 ferritic stainless steel were Cr_(23)C_6,Mn_(23)C_6,and Cr_7C_3,and the primary strengthening mechanism was precipitation strengthening.When Ti was added separately,the main precipitates were TiC and TiN.However,coarse TiC adversely affected the mechanical properties of steel.When double-stabilized with Ti and Nb,coarse TiC was replaced by fine NbC.The type of precipitation was altered,and precipitation and solid solution strengthening occurred.Therefore,the tensile strength and plastic strain ratio(r-value) improved to 433.60 MPa and 1.37,respectively.     

Microstructure and mechanical properties of a high strength and high corrosion resistance roll-bonded clad checkered plate

The checkered plate,also known as the floor/pattern plate,has a raised pattern that provides excellent skid resistance for a wide range of applications. As one of most commonly used products,the carbon steel checkered plate requires a high-cost coating for corrosion resistance. Although the austenitic stainless steel checkered plate meets corrosion resistance requirements,it does not necessarily provide high overall performance due to its low yield strength,which means greater thickness and weight. Combining the advantages of stainless and carbon structural steel,Baosteel has developed a new roll-bonded clad checkered plate that exhibits high performance in skid resistance,strength,and corrosion resistance. Metallographic analysis show s the cladding interfaces to be very good,with stainless steel filling the whole pattern and a uniform microstructure in the different cladding layers. The yield strength and tensile strength of the product are 470 MPa and 610 MPa,respectively. In addition,the fracture morphology exhibits excellent interfacial bonding properties. We performed external and internal bend tests at room temperature,180°,and 0.7a without the development of any cracks,which indicates its excellent formability.     

Effect of samarium on microstructure and corrosion resistance of aged as-cast AZ92 magnesium alloy

The effects of samarium（Sm） on microstructure and corrosion resistance of AZ92 magnesium alloy were characterized and analyzed by scanning electronic microscopy, X-ray diffraction, mass loss test, electrochemical impedance spectroscopy, X-ray photoelectron spectroscopy and potentio-dynamic polarization test. The results showed that the added Sm could promote continuous precipitation of β-Mg17Al12 phase in grains, and meanwhile restrain discontinuous precipitation of the same phase along the grain boundaries. Thus, the precipitations distributed more uniformly in the aged AZ92 magnesium alloys. When the content of Sm was 0.5 wt.%, the corrosion resistance of aged AZ92 alloy tended to be the best, which was due to the β-phase distributes more homogeneous reducing the galvanic corrosion. The corrosion product film had more integrality and compactness than AZ92 alloys without Sm. However, it resulted in worse corrosion resistance of AZ92 alloy because of the formation of mass cathodic Al2 Sm phase coming from excess Sm in AZ92 alloy.     

硼含量对Ni-Cr-Mo合金热腐蚀性能的影响

采用真空液相烧结法制备了4种掺加不同B含量的Ni-Cr-Mo合金,研究了B对其组织与性能的影响。研究结果表明,B与Mo、Cr、Ni等合金元素在烧结时可以形成共晶液相,通过原位化学反应,生成Mo2NiB2、(Mo,Cr)2NiB2陶瓷相。热腐蚀性试验表明,形成的硼化物相具有较好的耐腐蚀性,能够有效提高Ni-Cr-Mo合金的耐热腐蚀性能。     

Influence of alloying elements and grain refiner on microstructure,mechanical and wear properties of Mg-Al-Zn alloys

In the present investigation, the effects of alloying elements (Sn, Pb) and grain refiner (Ag, Zr) on microstructure, mechanical and wear properties of as-cast Mg-Al-Zn alloys were studied. The alloys were prepared through melting-casting route under a protective atmosphere and cast into a permanent mould. The microstructure of the base alloy consisted of α-Mg, Mg₁₇Al₁₂ continuous eutectic phase at the grain boundary and Mg-Zn phase was distributed within the grains. Addition of Sn and Pb suppressed the formation of continuous Mg₁₇Al₁₂ eutectic phase and formed Pb enriched Mg₂Sn precipitates at the grain boundary as well as inside the grain. The Ag and Zr addition to Mg-Al-Zn-Sn-Pb alloy suppressed the Mg₁₇Al₁₂ phase formation and refined the grains leading to improve mechanical properties. Addition of Sn, Pb and grain refiner (Ag, Zr) significantly enhanced the tensile strength and elongation but reduced hardness. The Ag addition imparted best tensile properties, where ultimate tensile strength (UTS) and elongation are 205?MPa and 8.0%, respectively. The fracture surfaces were examined under SEM which revealed cleavage facets and dimple formation. Therefore, the cleavage fracture and dimple rupture were considered as the dominant fracture mechanisms for developed Mg alloys. The cumulative volume loss of Mg alloys increased with sliding distance and applied load. The coefficient of friction decreased with sliding distance. The microscopic observation, analysis of the wear surface and coefficient of friction revealed that the wear mechanism of developed Mg alloys changes from abrasion oxidation to delamination wear.     

Cu,Mg含量对Al-xCu-yMg-0.6Ag合金力学性能的影响

采用铸锭冶金以及形变热处理工艺,制备了不同Cu,Mg含量的Al-xCu-yMg-0.6Ag合金.通过拉伸性能测试、差热分析(DSC)以及扫描电镜(SEM)与透射电镜(TEM)分析,研究Cu,Mg含量对合金组织与力学性能的影响.结果显示:增加Cu与Mg的含量,能提高基体合金的时效硬化效果与抗拉强度.185℃峰时效时,Al-xCu-yMg-0.6Ag合金的主要强化相由片状Ω相和少量θ'相组成.随着Cu含量的增加,峰时效态合金中Ω相体积分数增大.增加Mg的含量,能加速合金的时效硬化过程,减小Ω相的尺寸.     

稀土Nd对AZ 31镁合金铸态组织和力学性能的影响

利用气氛电阻炉制备了AZ 31-xNd合金(x=0.05%,0.1%,0.2%,0.4%,0.6%),采用光学显微镜(OM)、扫描电子显微镜(SEM)和电子能谱分析仪(EDS)对不同Nd含量的实验合金进行了显微组织观察和分析,结果发现,Nd在AZ 31-xNd合金中形成了Al_3Nd和Mg_(12)Nd相,这些含Nd相导致AZ 31镁合金在凝固过程中的晶粒细化,从而提高了AZ 31镁合金的铸态室温力学性能,随着Nd含量的增加,合金的铸态室温抗拉强度极限和延伸率均先升高后降低.     

热处理工艺对GH4706合金显微组织与力学性能的影响

为掌握热处理工艺对GH4706合金组织性能的影响规律,研究了A、B、MST三种热处理工艺与合金组织性能的相关关系.结果表明,GH4706合金的主要强化相为γ＇相与γ＇/γ″共析出相,η相附近易形成γ＇、γ″相贫化区.A工艺在中间时效阶段析出的大尺寸γ＇相与时效阶段析出的小尺寸γ＇/γ″共析出相能够起到错配强化的效果,增大合金的室温拉伸强度.室温下η相为脆性相,不利于室温拉伸塑性与冲击韧性,因而B工艺的室温塑性与冲击韧性最佳.高温下η相能够起到协调晶内与晶界变形的作用,提高合金的650℃/690 MPa持久寿命与塑性,但过量η相析出不利于合金的持久寿命.     

Microstructure and mechanical properties of Mg-Zn-Mn-Sn-Nd wrought alloys

The microstructure and mechanical properties of as-cast and extruded Mg-6Zn-1Mn-4Sn-xNd(x=0, 0.5, 1.0, 1.5) alloys were investigated by means of optical microscopy(OM), X-ray diffraction(XRD), scanning electron microscopy(SEM) and tensile test. The results showed that the dendrites sizes of these alloys were decreased by the addition of Nd. The phase compositions of the as-cast Mg-Zn-Mn-Sn-Nd alloys were dendritic α-Mg, MgZn2, Mg2 Sn, T phase and MgSnNd ternary phase. The mechanical properties of the as-extruded alloys were improved due to the refined equiaxed grains and dispersive Mg2 Sn and MgSnNd second phases. The comparison of the theoretical yield strength with the experimental yield strength revealed that the yield strength model of the as-extruded alloys should be modified as σys =σMg +σgb +σss +σsp.