粉末冶金法制备SiCp/6061Al复合材料的热释放现象

利用机械合金化-粉末冶金制备了SiCp/6061Al复合材料。对实验中发现的一种热释放现象进行了计算机在线测量和初步分析。实验表明，经机械合金化后制备的SiCp/6061Al复合材料中增强体分布均匀，在固溶水淬后有明显的热释放现象，而且热释放的程度与粉末的尺寸、试样的状态有关。试样在室温自然状态下，温度可升高至80℃左右。     

粉末冶金法制备粉煤灰/铝基复合材料的研究

采用粉末冶金法制备粉煤灰增强铝基复合材料。粉煤灰颗粒大多为球形，密度为2．75g／cm^3，颗粒直径主要集中在5～60μm，主要成分为SiO2、Al2O3、Fe2O3，三者质量分数总和超过85％。SEM分析表明铝基粉煤灰复合材料中存在着颗粒团聚，并有少量气孔产生。随粉煤灰颗粒含量的增加，复合材料的显微硬度相应减小。     

粉末冶金法制备泡沫铝材研究进展

介绍了泡沫铝材的用途和应用前景，国内外的研究现状，重点阐述了采用粉末冶金法制备泡沫铝材的基本原理、工艺流程，与其它方法比较的优缺点。对粉末冶金法制备泡沫铝过程的制坯压力、发泡剂量、发泡温度、发泡时间等参数对发泡过程的影响进行了讨论，分析了泡沫铝研究的现存问题及发展趋势。     

烧结规范对粉末冶金法制备的SiCp/Al复合材料挤压态力学性能的影响

实验研究了烧结规范对粉末冶金法制备的SiCp/Al复合材料挤压态力学性能的影响 ,测定了不同烧结规范下该材料在直接挤压态和挤压后T6态的力学性能 ,从而优化了该材料的烧结规范。     

用粉末冶金法制备Cf-Al复合材料研究

以镀铜碳纤维和铝粉作原料,采用粉末冶金法制备了碳纤维增强铝基复合材料,并研究了压制力、烧结温度和碳纤维含量对复合材料性能的影响。结果表明,碳纤维含量为5％（质量分数）、压制力小于150MPa时,坯体的密度随着压制力的增大而快速增大;若压制力超过150MPa,则坯体密度随着压制力增大而缓慢上升;低温下,随着烧结温度的上升,复合材料的密度缓慢增大,强度也上升;但高温下,随着烧结温度的上升,材料密度上升速度加快,强度略降。复合材料烧结前后的密度均随着碳纤维含量的增加而降低。     

SiC_p/2024Al铝基复合材料的耐蚀性

用电化学方法和浸泡试验研究了SiC颗粒粒度和体积分数对SiCp/ 2 0 2 4Al铝基复合材料在 3.5 %NaCl水溶液中耐蚀性的影响 ,作为比较对 2 0 2 4Al的耐蚀性也进行了研究。结果表明 ,与基体相比 ,SiCp/ 2 0 2 4Al复合材料并不增加点蚀敏感性 ,其抗蚀性与SiC体积分数和粒度有关 ,SiC颗粒体积分数低或粒度高的复合材料 ,其抗蚀性往往大。     

粉末冶金法制备泡沫铝材料发泡过程中孔形态的演变

对采用粉末冶金法制备泡沫铝材料进行研究.详细讨论了发泡时间对泡沫铝密度、孔隙率的影响,描述了发泡过程孔结构的演变过程,并对发泡机理进行分析.在发泡过程中,氢气压力作为膨胀动力,在开始阶段,压力随着时间的增加而增大,气泡长大;达到一定值后,由于气泡过度生长而发生破裂,形成塌缩.     

二次热压变形工艺对粉末冶金SiC_p/Al复合材料组织均匀性的影响

采用粉末冶金法在普通空气加热炉中烧结制备了不同 Si C含量的 Si Cp/ Al复合材料 ,并对其组织的均匀性作了研究。结果表明 ,对 Si Cp/ Al复合材料进行二次热压变形 ,可改善复合材料组织的不均匀性 ,使基体晶粒细化 ,Si C颗粒分布均匀 ,致密度提高。通过对不同热压工艺进行比较 ,发现 40 0℃× 190 k N× 10 min热压变形工艺对改善 Si Cp/ Al复合材料组织的不均匀性效果更好。     

粉末冶金工艺制备的钛基复合泡沫材料的压缩性能和弹性模量(英文)

钛基复合泡沫材料由于其优异的生物相容性、抗腐蚀性以及可改的弹性模量,具有极大的生物医用潜力。采用粉末冶金工艺制备嵌入厚壁陶瓷微珠的钛基复合泡沫材料。分析和测试这种钛基复合泡沫材料的微观结构、压缩性能以及弹性模量。结果表明:厚壁陶瓷微珠能够显著提高材料的抗压强度;提高厚壁陶瓷微珠的体积分数,能够使材料的抗压强度获得极大的提高,同时,这种强度的提高并没有引起弹性模量的显著提高。该材料的弹性模量仍然与人体骨骼相近。     

以TiH_2为发泡剂制备泡沫铝的研究现状

探讨了发泡剂发泡法、粉末冶金发泡法、累积叠轧焊法中以TiH2为发泡剂制备泡沫铝的研究进展.在发泡剂发泡法中,对TiH2发泡剂高温下分解过快问题采取了热处理、化学改性、包覆等方法以减缓其释气速率,使泡沫铝生产易于控制;在粉末冶金发泡法、累积叠轧焊法制备泡沫铝夹心板的过程中,后者更有利于TiH2发泡剂的均匀分布.     

Preparation and characterization of SiCp/2024Al composite foams by powder metallurgy

SiC_p/2024Al composite foams were manufactured by powder metallurgical methods using foaming agent CaCO₃ in order to enrich the foam fabrication process and promote its development and extensive application. The effects of CaCO₃ and SiC volume fractions on the foaming behaviours were investigated by means of SEM and Magiscan-2A image analysis technique. The influence of SiC content on the compressive behaviour was analyzed using Gleeble 1500 thermal simulation testing machine. The experimental results show that with increasing the foaming agent, the porosity and pore dimension increase first and decrease later. With increasing the reinforcement content, the porosity and pore dimension decrease. The compressive curves reveal that the introduction of SiC particles can improve compressive yield strength and energy absorption capacity. Meanwhile, it is found that SiC_p/2024Al composite foams are the brittle foam materials.     

Effects of foaming parameters on microstructure and compressive properties of aluminum foams produced by powder metallurgy method

Semi open-cell aluminum foams having channels between individual cells were produced using low cost CaCO₃ foaming agent and applying the powder compact melting process. To this end, the aluminum and CaCO₃ powder mixtures were cold compacted into dense cylindrical precursors for foaming at specific temperatures under air atmosphere. The effects of several parameters including precursor compaction pressure, foaming agent content as well as temperature and time of the foaming process on the cell microstructure, linear expansion, relative density and compressive properties were investigated. A uniform distribution of cells with sizes less than 100 μm, which form semi open-cell structures with relative densities in the range of 55.4%–84.4%, was obtained. The elevation of compaction pressure between 127–318 MPa and blowing agent up to 15% (mass fraction) led to an increase in the linear expansion, compressive strength and densification strain. By varying the foaming temperature from 800 to 1000 °C, all of the investigated parameters increased except compressive strength and relative density. The results indicated the optimal foaming temperature and time as 900 °C and 10–25 min, respectively.     

SiC_p/2024铝合金复合材料粉末混合半固态挤压法制备

研究了SiCp/ 2 0 2 4铝合金复合材料的粉末混合 半固态挤压成形工艺及所制备材料的组织和界面特征。不同温度下半固态挤压的挤压力与位移曲线表明 ,半固态挤压过程的成形力低且稳定。SEM和TEM电镜观察结果表明 ,该工艺可以获得增强颗粒分布均匀、基体组织致密、界面结合良好且无界面反应的复合材料型材。分析了半固态挤压后复合材料的力学性能 ,结果表明 :与基体合金相比 ,复合材料的弹性模量、屈服强度、抗拉强度均有很大提高 ;与其它工艺生产的该复合材料相比 ,所制备的复合材料的塑性相对较高。     

Compressive characteristics of closed-cell aluminum foams with different percentages of Er element

In the present study, closed-cell aluminum foams with different percentages of erbium(Er) element were successfully prepared. The distribution and existence form of erbium(Er) element and its effect on the compressive properties of the foams were investigated. Results show that Er uniformly distributes in the cell walls in the forms of Al3 Er intermetallic compound and Al-Er solid solutions. Compared with commercially pure aluminum foam, Er-containing foams possess higher micro-hardness, compressive strength and energy absorption capacity due to solid solution strengthening and second phase strengthening effects. Additionally, the amount of Er element should be controlled in the range of 0.10 wt.%-0.50 wt.% in order to obtain a good combination of compressive strength and energy absorption properties.     

热处理过程中SiCp/2024Al基复合材料的微观组织演变

采用真空热压烧结工艺在580℃下制备了35%(体积分数)SiCp/2024铝基复合材料,利用扫描电镜(SEM)、透射电镜(TEM)、能谱(EDS)、高分辨透射电镜(HRTEM)对复合材料热处理过程中微观组织进行了表征,研究了热压烧结后复合材料的析出相的微观结构以及析出相在热处理过程的演变规律。结果表明,热压烧结后复合材料中存在许多粗大析出相颗粒,包括Al4Cu9,Al2Cu,Al18Mg3Mn2,Al5Cu6Mg2和Al7Cu2Fe。随着固溶温度的提高,粗大析出相颗粒逐渐回溶到Al基体中,当固溶温度达到510℃时,粗大析出相颗粒几乎全部回溶到基体中,但还存在少量的难溶相。复合材料经510℃固溶2 h+190℃时效9 h后,除了少量的难溶相,许多圆盘状纳米析出相Al2Cu和棒针状纳米析出相Al2Cu Mg弥散分布于基体中且与基体的界面为错配度较小的半共格界面,圆盘状纳米析出相的直径为50~200 nm,棒针状纳米析出相长度为100~150 nm。     

搅拌铸造SiC_p/2024铝基复合材料的显微组织与力学性能

利用搅拌铸造?热挤压工艺制备SiCp/2024铝基复合材料板材,研究该复合材料铸态、热挤压态和热处理态的显微组织及力学性能。结果表明:SiC颗粒较均匀地分布于铸锭中,大部分SiC颗粒沿晶界分布,少数颗粒分布于晶内,晶界粗大的第二相呈非连续状分布;复合材料经热挤压变形后,显微孔洞等铸造缺陷明显消除,破碎的晶界第二相及SiC颗粒沿热挤压方向呈流线分布,复合材料的强度和塑性显著提高;对热挤压板材进行(495℃,1h)固溶处理+(177℃,8h)时效处理后,其抗拉强度达430MPa,此时的主要析出强化相为S′(Al2CuMg);热挤压变形有利于改善SiC颗粒与基体合金的界面结合,热处理SiCp/2024铝基复合材料的主要断裂方式为基体合金的延性断裂、SiC颗粒断裂和SiC/Al的界面脱粘。     

喷射共沉积SiC_p/2024复合材料的显微组织与力学性能

利用喷射共沉积-热挤压-轧制工艺制备SiC_p/2024复合材料板材.研究该复合材料轧板热处理后的显微组织及力学性能,并确定其最佳的热处理工艺条件.结果表明:轧制态复合材料组织细小均匀,晶粒尺寸为3～4 μm,SiC颗粒均匀分布在基体合金中;采用490 ℃、1 h固溶处理和170 ℃、8 h时效后,SiC_p/2024复合材料轧板的抗拉强度、屈服强度和伸长率分别为480 MPa、358 MPa和6.4%,基体合金中存在大量细小的第二相颗粒,为Al_2MgCu及Al_2Cu相;峰时效状态时复合材料的布氏硬度值为228 HB,与轧板原始硬度相比较增幅达130%;喷射共沉积SiC_p/2024复合材料轧板到达峰时效时间比铸造2024铝合金的短,这主要是因为喷射沉积基体合金内细小均匀的晶粒组织、基体合金内高密度的位错组态以及SiC颗粒的引入,均有利于沉淀相的提前析出.     

Warm compaction of Al2O3 particulate reinforced powder metallurgy iron-base composite

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Superplastic deformation of SiCp/2024 Al composite fabricated by spray atomization and codeposition

In this paper, data are presented on the microstructure and superplastic deformation mechanics of an aluminum alloy, 2024, containing 10 vol% SiC particles. The material was fabricated by spray atomization and codeposition. The properties were studied after pretreatment by isothermal hot compression and isothermal hot forward extrusion (extrusion ratio 10.0). The experimental results show that the strain-rate sensitivity index (m-value) is 0.48 and the limit elongation (the elongation at fracture) is 345 % during superplastic uniaxial tension. The optimum conditions for superplastic behavior are 753 K of deformation temperature and 1.0 × 10⁻³ s⁻¹ of initial strain rate. Superplasticity may result from the fine grain size and the well-distributed SiC particles during superplastic uniaxial tension. Moreover, the simple and convenient pretreatment used in this paper is easily applied to industrial practice.