晶粒尺寸的影響
(1.重慶大學(xué) 機(jī)械工程學(xué)院, 重慶 400044;
2.重慶鎂業(yè)股份有限責(zé)任公司, 重慶 400051；
3.西南鋁業(yè)(集團(tuán))有限責(zé)任公司 技術(shù)中心，重慶 401326)
摘 要: 對(duì)LY12合金采用形變誘導(dǎo)法制備半固態(tài)合金料坯的組織演變過(guò)程進(jìn)行了觀(guān)察，對(duì)變形率、半固態(tài)溫度、半固態(tài)保溫時(shí)間對(duì)合金半固態(tài)組織和晶粒尺寸的影響進(jìn)行了研究。組織演變過(guò)程觀(guān)察表明：用形變誘導(dǎo)法制備該合金半固態(tài)坯料的合適的半固態(tài)重熔溫度為618℃；合金在該溫度重熔過(guò)程中，形變帶狀組織首先分解為細(xì)小的α多邊形晶粒，隨保溫時(shí)間的延長(zhǎng)，晶粒尺寸逐漸變大，同時(shí)α相逐漸球化；在相同的半固態(tài)溫度和相同的保溫時(shí)間下，宏觀(guān)變形率大的晶粒尺寸要比變形率小的合金組織晶粒尺寸小；變形率大的試樣比變形率小的液相出現(xiàn)時(shí)間早；在同一宏觀(guān)變形率下，試樣內(nèi)部微觀(guān)形變大的部位晶粒尺寸要比形變小的部位晶粒尺寸小。
關(guān)鍵字: 形變誘導(dǎo)法；LY12鍛造合金；半固態(tài)重熔；半固態(tài)組織；晶粒尺寸
factors on structure and grain size
of LY12 alloy in SIMA processing
XIE Shao-jun3, FAN Yun-qiang3
（1.College of Mechanical Engineering，Chongqing University，
Chongqing 400044，China；
2.Chongqing Magnesium Industry Ltd. Co., Chongqing 400051, China;
3.Technology Centre, Southwest Aluminum Industry Ltd. Co.,
Chongqing 401326, China）
Abstract:Structure evolution of LY12 alloy in remelting procedure in strain induced melt activated (SIMA) semi-solid processing was observed，and effects of the factors，remelting temperature，holding time and strain rate，on structure and grain size of the alloy were investigated. The results show that the proper remelting temperature is 618℃ and in the remelting procedure，small polygon α crystals are initially formed from breaking the original strip structure obtained during pressing and then grow larger along with more spherical shape. The grain size in the specimen with greater strain rate is smaller than that with smaller one in the same remelting temperature and holding time. Liquid emerges earlier in the specimen with greater strain rate than in the specimen with smaller macroscopic strain rate. The grain size in the location with greater microscopic strain rate in a specimen with a certain macroscopic strain rate is smaller than that in the location with smaller microscopic strain rate.
Key words: strain induced melt activated processing；LY12 forging alloy； remelting in semi-solid temperature；semi-solid structures；grain sizes
