不同热成形工艺下TA32钛合金的流变性能及组织演变

用OM,SEM和XRD等方法研究了挤压态Mg-Al-Ca-x Nd(x=0~1.76,质量分数,%)合金的显微组织和析出相以及该合金在室温和高温下的力学性能。结果表明,Nd的添加会使基体中形成Al2Nd和Al11Nd3相,并且细化Mg-Al-Ca合金的晶粒。随着Nd添加量的增加,Al2Nd和Al11Nd3相的数量也随之增加。当添加1.76%Nd时,合金的平均晶粒尺寸从不含Nd的4.80μm变为2.39μm。由于第二相的析出和晶粒细化,室温下的力学性能也得到改善。随着Nd元素含量的增加,合金的室温抗拉伸强度由267MPa提高到304 MPa,屈服强度从144 MPa提高到203 MPa,延伸率从20.0%下降到16.9%。在150℃时,随着Nd含量的增加,拉伸强度从192 MPa增加到229 MPa,屈服强度从140 MPa增加到159 MPa,伸长率从48.6%下降到29.3%。

Study on Rheological Properties and Microstructure Evolution of TA32 Titanium Alloy under Different Thermoforming Processes

The microstructures and precipitated phases of as-extruded Mg-Al-Ca-x Nd alloys with x=0 wt%~1.76 wt%Nd were studied by OM,SEM and XRD.The mechanical properties of the alloys at room temperature and high temperature were also tested.Results show that the addition of Nd results in the formation of Al2 Nd and Al11 Nd3 phases in the matrix and the grain refinement of Mg-Al-Ca alloy,and the amount of Al2 Nd and Al11 Nd3 phases increases with the increase of Nd addition.The average grain size of these alloys changes from 4.80μm(without Nd)to 2.39μm(with 1.76 wt%Nd added).The mechanical properties at room temperature are improved due to the precipitation of the second phases and grain refinement.With increment of Nd,the tensile strength increases from 267 MPa to 304 MPa,the yield strength increases from 144 MPa to 203 MPa and the elongation decreases from 20.0%to 16.9%at room temperature.At 150°C,the tensile strength increases from 192 MPa to 229 MPa,the yield strength increases from 140 MPa to 159 MPa and the elongation decreases from 48.6%to 29.3%with increasing the Nd content.