A0721半固态合金二次加热工艺和组织演化机制.pdfVIP

铸 造 VoI．53 NO．8 · 590 · FOUNDRY Aug．2004 A2017半固态合金二次加热工艺及组织演化机制 王顺成，温景林，陈彦博，曹富荣，李英龙 (东北大学材料与冶金学院。辽宁沈阳 110004) 摘要 ：相同加热温度条件下。随着保温时间的延长，晶粒逐渐长大和球化，液相分数增加；提高二次加热温度。晶粒 长大和球化速度加快。在62O～625℃加热，保温4O～60min。可获得 由均匀球形晶粒悬浮于液相组成的半固态组织， 晶粒大小为7O～90pm。液相率为40％～45％。而常规铸造枝 晶A2017合金坯料二次加热后仍然保留粗大的枝晶网络结 构。半固态合金锭坯二次加热初期晶粒的熔合合并是晶粒长大的主要方式，相界面能的升高和相界面表面张力是组织 演化的主要驱动力。 关键词 ：半固态金属；二次加热；A2017合金；组织演化 中图分类号：TG249．9；TG146．2 文献标识码：A 文章编号 ：1001．4977 (2004)08．0590．05 ReheatingProcessandMicrostructureEvolutionMechanism of theSemi-solidA2017AlloyDuringReheatinginSemi-solidState WANG Shun-cheng，WENJing-lin，CHENYan-bo，CAO Fu-rong，LIYing-long (SchoolofMaterialsandMetallurgy，NortheasternUniversity，Shenyang110004，Liaoning，China) Abstrach The semi．solidA2017billetsprovidedwith shearing-cooling-rolling (SCR) processwere reheated．Thereheating processand the mechanism ofmicrOstructure evolutionwere researched．The resultsindicated thatthemeandiameterofgrains increaseswiththe prolongation ofisothermaIholding time，withgrainssphericizedmoreandmoreandliquidfractionincreased．Inaddition，thegrainsgrow up andare sphericizedfasteras the reheating temperature jsrising．Underthecombination ofreheating temperature620～625℃ andholdingtime40～60min。themicrostructurewithmeandiameterofgrains 70 ～ 90um andIiquidfraction40％ ～45％ canbeobtained．However，themicrostructureofas-castbillets reheated in semi-soIid state was transformed into dendritic-network structure． The analysis of the microstructuraIevolutionmechanism showed thatinthe earlystage ofthewhole reheating process，the grainsgrow upfastlymainlythroughcoalescence．Thedrivingforceofgrains coarseningandspheroidizing isphaseinterfaceenergyincreasingand interfacialtens ion． Keywords：semi．solid