粉末冶金材料科学与工程
粉末冶金材料科學與工程
분말야금재료과학여공정
POWDER METALLURGY MATERIALS SCIENCE AND ENGINEERING
2015年
3期
331-337
,共7页
Al-Si20合金粉末%包套-等径角挤压%挤压路径%致密化行为%组织性能
Al-Si20閤金粉末%包套-等徑角擠壓%擠壓路徑%緻密化行為%組織性能
Al-Si20합금분말%포투-등경각제압%제압로경%치밀화행위%조직성능
Al-Si20 alloy powder%PITS-ECAP%different ECAP path%densification behavior%microstructure and properties
在500℃下采用包套?等径角挤压(PITS-ECAP)工艺将Al-Si合金粉末颗粒固结成高致密、块体细晶材料。结果表明，PITS-ECAP 工艺对粉末材料具有强烈的致密化效果。1道次 PITS-ECAP 后，试样整体相对密度比初始预装粉致密度提高了50%；2道次 PITS-ECAP 工艺变形后，合金粉末初晶硅明显细化、整体致密化强烈，C路径能高效破碎组织中粗大板片状初晶硅，使晶粒尺寸变小，圆整度提高，分布均匀，粉末材料相对密度达95%，显微硬度值增加到220 HV25，初晶硅形状系数为0.64，致密化及初晶硅细晶化效果最好；A路径虽致密效果不好但有利于等温处理后的初晶硅细晶化，Bc路径产生的初晶硅细晶化、致密化效果较差。在PITS-ECAP工艺变形过程中，剧烈塑性剪切变形、较高静水压力和有效应变积累是合金粉末致密化、初晶硅细晶化的主要驱动因素。
在500℃下採用包套?等徑角擠壓(PITS-ECAP)工藝將Al-Si閤金粉末顆粒固結成高緻密、塊體細晶材料。結果錶明，PITS-ECAP 工藝對粉末材料具有彊烈的緻密化效果。1道次 PITS-ECAP 後，試樣整體相對密度比初始預裝粉緻密度提高瞭50%；2道次 PITS-ECAP 工藝變形後，閤金粉末初晶硅明顯細化、整體緻密化彊烈，C路徑能高效破碎組織中粗大闆片狀初晶硅，使晶粒呎吋變小，圓整度提高，分佈均勻，粉末材料相對密度達95%，顯微硬度值增加到220 HV25，初晶硅形狀繫數為0.64，緻密化及初晶硅細晶化效果最好；A路徑雖緻密效果不好但有利于等溫處理後的初晶硅細晶化，Bc路徑產生的初晶硅細晶化、緻密化效果較差。在PITS-ECAP工藝變形過程中，劇烈塑性剪切變形、較高靜水壓力和有效應變積纍是閤金粉末緻密化、初晶硅細晶化的主要驅動因素。
재500℃하채용포투?등경각제압(PITS-ECAP)공예장Al-Si합금분말과립고결성고치밀、괴체세정재료。결과표명，PITS-ECAP 공예대분말재료구유강렬적치밀화효과。1도차 PITS-ECAP 후，시양정체상대밀도비초시예장분치밀도제고료50%；2도차 PITS-ECAP 공예변형후，합금분말초정규명현세화、정체치밀화강렬，C로경능고효파쇄조직중조대판편상초정규，사정립척촌변소，원정도제고，분포균균，분말재료상대밀도체95%，현미경도치증가도220 HV25，초정규형상계수위0.64，치밀화급초정규세정화효과최호；A로경수치밀효과불호단유리우등온처리후적초정규세정화，Bc로경산생적초정규세정화、치밀화효과교차。재PITS-ECAP공예변형과정중，극렬소성전절변형、교고정수압력화유효응변적루시합금분말치밀화、초정규세정화적주요구동인소。
The densification behavior of equal channel angular pressing for Al-Si20 alloy powders in capsule was studied. Al-Si20 alloy powder particles were successfully consolidated into full dense bulk material with fine grains at 500℃ by the powders in capsule-equal channel angular pressing (PITS-ECAP). The results show that PITS-ECAP process has a strong densification effect on the powder material, and the relative density of the sample as a whole is creased by 50% compared to the initial pre-powder density under the first PITS-ECAP process; After 2 passes of PITS-ECAP, there exists obvious refinement for early crystal silicon alloy powders and the overall strong densification for Al-Si20 alloy powder. Primary Si in Al-Si20 alloy powders are refined to spherical shape and crystal dimension is diminished, and the round and homogeneous grains are obtained; and overall relative density is 95%, the microhardness is 220 HV25, and average particle shape factor is about 0.64 via route C process, so route C is the best one for densification and grain refinement of primary silicon. Route A is not good to densification behavior but in favor of grain refinement of primary silicon isothermal treatment after 2 passes of PITS-ECAP, and route Bc process is inefficient for the densification and grain refinement of primary silicon, too. It is also indicated that the severe plastic shear deformation, high hydrostatic pressure and the cumulation effective strain ensure a high density and a fine microstructure of powder consolidate.
