摘要
Pouring and mold temperatures are two important parameters during casting magnesium components. The present study examined their influence on hot tearing susceptibility （HTS） of commercial AZ91D and newly developed Mg-3Nd-0.2Zn-Zr （mass fraction, %; NZ30K） magnesium alloys in gravity permanent mold casting condition. The results indicate that mold temperature shows much more significant influence on the HTS of both alloys than pouring temperature whose influence only can be distinguished at low mold temperature （341 K for AZ91D alloy and 423 K for NZ30K alloy）. Hot tearing susceptibility prediction model concerning feeding parameters, grain size and solidification range, is more suitable to estimate the HTS of different magnesium alloys than the model only concerning feeding parameters. In order to achieve better hot tearing resistance, the ranges of pouring and mold temperatures are suggested to be 961-991 K and≥641 K for AZ91D alloy, 1003-1033 K and≥623 K for NZ30K alloy, respectively.
研究了浇铸温度和模具温度两个温度参数在重力金属型铸造中对商业AZ91D和新型Mg-3Nd-0.2Zn-Zr （质量分数，%；NZ30K）镁合金热裂性能的影响。结果表明，模具温度对合金热裂性能的影响比浇铸温度的更显著，后者的影响仅在模具温度较低时（AZ91D在341 K，NZ30K在423 K）有所显现。与只包含补缩参数的热裂模型相比，同时包含补缩参数、晶粒尺寸和合金凝固区间的热裂模型更能够准确地评价不同镁合金的热裂性能。为了获得较好的热裂抗力，建议AZ91D合金的浇铸温度为961~991 K，模具温度≥641 K；NZ30K合金的浇铸温度为1003~1033 K，模具温度≥623 K。
基金
Project (2009AA033501) supported by the High-tech Research and Development Program of China
