简介:以两种Al2O3-Al2TiO5复合粉体为原料经SPS烧结制备出Al2O3-Al2TiO5复相陶瓷。采用纳米结构复合粉体烧结而成的复相陶瓷有着较优的力学性能,特别是具有较高的断裂韧性和硬度,与其较小的晶粒尺寸相对应。干滑动摩擦磨损试验在4N和6N法向载荷下进行,结果表明,采用微米结构复合粉体烧结而成的复相陶瓷磨损表面较光滑,体积磨损量较小。在磨损试验中,纳米结构复合粉体烧结而成的复相陶瓷的破坏方式为沿晶断裂,有明显的晶粒拔出现象;微米结构复合粉体烧结而成的复相陶瓷呈不连续的微观断裂并产生塑性变形;同时,两种材料在摩擦磨损过程中都发生接触面的氧化和物质转移。
简介:半--压克力吃了的乙酸乙烯酯和丁基的连续播种乳剂copolymerizalion作为胶体stabilizer与hydroxyethyl纤维素被执行。在反应时间和平均粒子直径and/或变换比率之间的乳胶粒子和关系的形态学在聚合期间被调查。试验性的结果证明乳胶粒子的形态学拥有稳定的位的构造。Inthe播种了聚合,当变换比率增加了时,乳胶的平均粒子直径减少了。在乳剂copohmerization(粒子尺寸的生长阶段)的第二个术语,乳胶粒子一般水准直径连续地与共聚化合物增加了,但是。即时谈话比率不大,因此适当地在成立温度阶段期间延长时间是很必要的。
简介:ThehomogeneousplasticflowoffullyamorphousandpartiallycrystallizedZr41.2Ti13.8Cu12.5Ni10Be22.5bulkmetallicglass(Vitl)hasbeeninvestigatedbycompressiontestsathightemperaturesinsupercooledliquidregion.Experimentalresultsshowthatatsufficientlylowstrainrates,thesupercooledliquidofthefullyamorphousalloyrevealsNewtonianflowwithalinearrelationshipbetweentheflowstressandstrainrate.Asthestrainrateisincreased,atransitionfromlinearNewtoniantononlinearflowisdetected,whichcanbeexplainedbythetransitionstatetheory.Overtheentirestrainrateintervalinvestigated,however,onlynonlinearflowispresentinthepartiallycrystallizedalloy,andtheflowstressforeachstrainrateismuchhigher.Itisfoundthatthestrainrate-stressrelationshipforthepartiallycrystallizedalloyatthegiventemperatureof646Kalsoobeysthesinhlawderivedfromthetransitionstatetheory,similartothatoftheinitialhomogeneousamorphousalloy.Thus,itisproposedthattheflowbehaviorofthenanocrystalline/amorphouscompositeat646Kismainlycontrolledbytheviscousflowoftheremainingsupercooledliquid.