中国有色金属学报（英文版）
中國有色金屬學報（英文版）
중국유색금속학보（영문판）
TRANSACTIONS OF NONFERROUS METALS SOCIETY OF CHINA
2013年
6期
1602-1609
,共8页
陈淑英%常国威%黄玉多%刘升阳
陳淑英%常國威%黃玉多%劉升暘
진숙영%상국위%황옥다%류승양
AZ31B镁合金%铸态组织%力学性能%熔体温度
AZ31B鎂閤金%鑄態組織%力學性能%鎔體溫度
AZ31B미합금%주태조직%역학성능%용체온도
AZ31B magnesium alloy%as-cast structure%mechanical properties%melt temperature
采用自制的电阻炉研究熔体温度对 AZ31B 镁合金凝固组织与拉伸性能的影响。结果表明：在温度低于850°C水冷时，金属型AZ31B镁合金铸锭等轴枝晶的尺寸随着熔体温度的升高呈直线下降，超过850°C后变化不大。组织中第二相呈现出先细化后粗化的变化规律。AZ31B镁合金试样的抗拉强度、伸长率和屈服强度随着熔体温度的提高而先快速增大后略有减小，熔体温度为850°C时试样的抗拉强度达到260 MPa，屈服强度达到75.4 MPa，伸长率达到27.57%，比熔体温度为750°C时的分别提高了15%、13%和61%。DSC分析表明，升高熔体温度使凝固开始点温度降低，临界晶核半径减小，从而增加了熔体中的过冷度，提高了熔体中非均匀形核率，是镁合金晶粒细化和拉伸性能提高的主要原因。
採用自製的電阻爐研究鎔體溫度對 AZ31B 鎂閤金凝固組織與拉伸性能的影響。結果錶明：在溫度低于850°C水冷時，金屬型AZ31B鎂閤金鑄錠等軸枝晶的呎吋隨著鎔體溫度的升高呈直線下降，超過850°C後變化不大。組織中第二相呈現齣先細化後粗化的變化規律。AZ31B鎂閤金試樣的抗拉彊度、伸長率和屈服彊度隨著鎔體溫度的提高而先快速增大後略有減小，鎔體溫度為850°C時試樣的抗拉彊度達到260 MPa，屈服彊度達到75.4 MPa，伸長率達到27.57%，比鎔體溫度為750°C時的分彆提高瞭15%、13%和61%。DSC分析錶明，升高鎔體溫度使凝固開始點溫度降低，臨界晶覈半徑減小，從而增加瞭鎔體中的過冷度，提高瞭鎔體中非均勻形覈率，是鎂閤金晶粒細化和拉伸性能提高的主要原因。
채용자제적전조로연구용체온도대 AZ31B 미합금응고조직여랍신성능적영향。결과표명：재온도저우850°C수랭시，금속형AZ31B미합금주정등축지정적척촌수착용체온도적승고정직선하강，초과850°C후변화불대。조직중제이상정현출선세화후조화적변화규률。AZ31B미합금시양적항랍강도、신장솔화굴복강도수착용체온도적제고이선쾌속증대후략유감소，용체온도위850°C시시양적항랍강도체도260 MPa，굴복강도체도75.4 MPa，신장솔체도27.57%，비용체온도위750°C시적분별제고료15%、13%화61%。DSC분석표명，승고용체온도사응고개시점온도강저，림계정핵반경감소，종이증가료용체중적과랭도，제고료용체중비균균형핵솔，시미합금정립세화화랍신성능제고적주요원인。
The effects of melt temperature on the as-cast structure and mechanical properties of AZ31B magnesium alloy were studied through a home-made electrical resistance furnace. The results show that the equiaxed dendrite size of AZ31B magnesium alloy under water-cooled metal cooling is linearly decreased with increasing the melt temperature below 850 °C, whereas the size changes little over 850 °C. The second phases in the microstructure are firstly refined;however, they are coarsened when the melt temperature exceeds 850 °C. With the increase of melt temperature, the tensile strength, yield strength and elongation of AZ31B magnesium alloy samples are rapidly enhanced first, then are slightly declined. When the melt temperature is increased to 850 °C, the tensile strength, yield strength and elongation reach 260 MPa, 75.4 MPa and 27.57%, respectively. The tensile strength, yield strength and elongation are increased by 15%, 13%and 61%, respectively compared with 750 °C. DSC analysis shows that the nucleation temperature is decreased, the critical nucleus radius is lessened with the increase of melt temperature, which increase the degree of supercooling and heterogeneity nucleation rate in melt, and the growth rate becomes larger with the increase of the degree of supercooling. That is the reason why the grain size is first rapidly decreased, and then is little increased.
