Adjustment of the Mechanical Properties of Mg2Nd and Mg2Yb by Optimizing Their Microstructures
Adjustment of the Mechanical Properties of Mg2Nd and Mg2Yb by Optimizing Their Microstructures
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DOI：
10.3390/met11030377
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发表时间：
2021-02
期刊：
影响因子：
2.9
通讯作者：
Jonas Schmidt;I. Beyerlein;M. Knezevic;W. Reimers
中科院分区：
文献类型：
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作者：
Jonas Schmidt;I. Beyerlein;M. Knezevic;W. Reimers
在室温下研究了挤压镁合金MG2ND和MG2YB的变形行为。通过使用原位能量分散性同步子X射线衍射压缩和拉伸测试，并伴随着弹性塑料自一致（EPSC）建模，分析了主动变形系统的差异。合金元件都会改变并削弱挤压纹理，并在挤压过程中形成沉淀，然后相对于常见的MG合金处理热处理。通过改变挤压参数和随后的热处理，可以在较大范围内调节强度和延展性，同时仍保持接近零的强度差异效应（SDE）。值得注意的是，在比较拉伸和压缩变形时，压缩和拉伸的屈服强度相似，没有机械各向异性，这对于工业应用是可取的。 MG2ND在压缩测试期间不常见的MG合金表现出低拉伸双重活性。我们表明，热处理可促进沉淀物的成核和生长，并增加同位素的屈服强度至200 MPa。屈服强度的各向异性降低至最小值，并且仍达到约0.2的伸长率。在较低的优势下，达到了高达0.41的伸长率。在MG2YB合金中，调整挤出参数可增强稀土纹理并减小晶粒尺寸。然而，观察到过度变形孪生，但是尽管如此，SDE仍被最小化。
The deformation behavior of the extruded magnesium alloys Mg2Nd and Mg2Yb was investigated at room temperature. By using in situ energy-dispersive synchrotron X-ray diffraction compression and tensile tests, accompanied by Elasto-Plastic Self-Consistent (EPSC) modeling, the differences in the active deformation systems were analyzed. Both alloying elements change and weaken the extrusion texture and form precipitates during extrusion and subsequent heat treatments relative to common Mg alloys. By varying the extrusion parameters and subsequent heat treatment, the strengths and ductility can be adjusted over a wide range while still maintaining a strength differential effect (SDE) of close to zero. Remarkably, the compressive and tensile yield strengths are similar and there is no mechanical anisotropy when comparing tensile and compressive deformation, which is desirable for industrial applications. Uncommon for Mg alloys, Mg2Nd shows a low tensile twinning activity during compression tests. We show that heat treatments promote the nucleation and growth of precipitates and increase the yield strengths isotopically up to 200 MPa. The anisotropy of the yield strength is reduced to a minimum and elongations to failure of about 0.2 are still achieved. At lower strengths, elongations to failure of up to 0.41 are reached. In the Mg2Yb alloy, adjusting the extrusion parameters enhances the rare-earth texture and reduces the grain size. Excessive deformation twinning is, however, observed, but despite this the SDE is still minimized.