組織和性能的影響
(北京有色金屬研究總院 有色金屬材料制備加工國家重點實驗室， 北京 100088)
摘 要: 對Mg-5.0Y-7.0Gd-1.3Nd-0.5Zr(EW75M)合金在不同條件下擠壓變形后的組織和性能進(jìn)行測試。結(jié)果表明：隨著擠壓比的增大，合金的強(qiáng)度和塑性均大幅度提高，當(dāng)擠壓比增大到20以后，晶粒細(xì)化對合金的強(qiáng)化效果趨于穩(wěn)定；當(dāng)擠壓筒溫度由400 ℃升高到450 ℃時，合金強(qiáng)度和伸長率的降幅均在5%以內(nèi)，擠壓筒溫度在400 ℃~ 450 ℃變化時對合金擠壓變形后的性能影響較小；將合金均勻化處理(535 ℃、24 h)后直接進(jìn)行擠壓變形(擠壓比20，擠壓筒溫度400 ℃，擠壓速度1~2 m/min)，其極限抗拉強(qiáng)度、屈服強(qiáng)度和伸長率分別達(dá)到335 MPa、240 MPa和16.5%。
關(guān)鍵字: 鎂合金；擠壓比；擠壓筒溫度；微觀組織；力學(xué)性能
（State Key Laboratory for Fabrication and Processing of Nonferrous Metals,
General Research Institute for Nonferrous Metals, Beijing 100088, China）
Abstract:The microstructures and mechanical properties of Mg-5.0Y-7.0Gd-1.3Nd-0.5Zr (EW75M) alloys extruded under different conditions were tested. The results indicate that both the strength and plasticity are improved with increasing extrusion ratio. When extrusion ratio is more than 20, the effect of grain refinement on strengthening has little improvement. When the extrusion tube temperature increases from 400 ℃ to 450 ℃, the average grain size has little increase, and both strength and elongation are decreased by less than 5%. After being hot treated at 535 ℃ for 24 h，EW75M alloy is directly extruded under conditions of extrusion ratio of 20, extrusion tube temperature of 400 ℃ and extrusion speed of 1−2 m/min. After being extruded, the ultimate tensile strength，yield strength and elongation of EW75M reach 335 MPa, 240 MPa and 16.5%, respectively.
Key words: magnesium alloy; extrusion ratio; extrusion tube temperature; microstructure; mechanical property
