摘要
AlSi10Mg合金具有高比强度、高耐磨性等优良特点。由于其成分接近共晶点,成形性能良好,被广泛应用于激光选区熔化技术。然而其热处理制度仍然沿用传统铸态合金的热处理规范,影响了其性能的充分发挥。本工作采用激光选区熔化技术制备了AlSi10Mg合金,并研究了沉积态和后续热处理过程中组织演化规律及其对室温力学性能的影响机制。研究发现:沉积态组织由沿沉积方向生长的α-Al柱状枝晶及枝晶间网状Al-Si共晶组成,具有强烈的〈100〉方向织构,沉积层由三部分组成,分别是细晶区、粗晶区及热影响区,抗拉强度389.5 MPa,伸长率4%。退火过程中,共晶Si破碎、球化,基体中过饱和Si不断析出长大。当退火温度从200℃提高到500℃时,Si颗粒发生Ostwald熟化,平均尺寸增长了23倍。经过300℃和500℃退火处理后,试样抗拉强度分别为287.0 MPa和268.0 MPa,但伸长率分别提高到10.3%和17.2%。
AlSi10Mg alloy has excellent characteristics such as high specific strength and good wear resistance.The composition of AlSi10Mg alloy is close to the eutectic point,thus it has good forming property and has been widely used in selective laser melting processing.However,for this moment,only the conventional annealing strategy is employed in the selective laser melted AlSi10Mg component,which greatly limits their further applications.In this work,the effects of several annealing on the microstructure and tensile properties of selective laser melted AlSi10Mg alloys were investigated.The results show that the as-fabricated sample presents a mixed structure of columnarα-Al and eutectic Al-Si structure along building direction,which possesses a strong texture ofα-Al〈100〉.The single molten pool consists of fine grain region,coarse grain region and heat affected region.The as-fabricated sample shows ultimate strength of 389.5 MPa with 4%elongation to failure.During the heat treatment,the eutectic Si is broken and spheroidized along with precipitation of supersaturated Al(Si).When the annealing temperature increases from 200℃to 500℃,the silicon particle suffers the Ostwald ripening for size increase of 23 times.The samples heat treated at 300℃and 500℃show the ultimate strength of 287.0 MPa and 268.0 MPa,and elongation of 10.3%and 17.2%,respectively.
作者
梁恩泉
代宇
白静
周亚雄
彭东剑
王清正
康楠
林鑫
LIANG Enquan;DAI Yu;BAI Jing;ZHOU Yaxiong;PENG Dongjian;WANG Qingzheng;KANG Nan;LIN Xin(COMAC Shanghai Aircraft Design and Research Institute,Shanghai 201210,China;State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xi’an 710072,China;Xi’an Space Engine Company Limited,Xi’an 710000,China)
出处
《材料工程》
EI
CAS
CSCD
北大核心
2022年第5期156-165,共10页
Journal of Materials Engineering
基金
国家重点研发计划(2016YFB1100100)
国家自然科学基金项目(52005411)。
关键词
激光选区熔化
增材制造
AlSi10Mg合金
热处理
组织演化
selective laser melting
additive manufacturing
AlSi10Mg alloy
heat treatment
microstructural evolution
