WO2020048539A1 - 一种提高aq80m镁合金强度和应变疲劳寿命的方法 - Google Patents

一种提高aq80m镁合金强度和应变疲劳寿命的方法 Download PDF

Info

Publication number
WO2020048539A1
WO2020048539A1 PCT/CN2019/104796 CN2019104796W WO2020048539A1 WO 2020048539 A1 WO2020048539 A1 WO 2020048539A1 CN 2019104796 W CN2019104796 W CN 2019104796W WO 2020048539 A1 WO2020048539 A1 WO 2020048539A1
Authority
WO
WIPO (PCT)
Prior art keywords
magnesium alloy
fatigue life
strength
aq80m
strain
Prior art date
Application number
PCT/CN2019/104796
Other languages
English (en)
French (fr)
Inventor
刘楚明
毛隆辉
万迎春
蒋树农
高永浩
Original Assignee
中南大学
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 中南大学 filed Critical 中南大学
Publication of WO2020048539A1 publication Critical patent/WO2020048539A1/zh

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C23/00—Alloys based on magnesium
    • C22C23/02—Alloys based on magnesium with aluminium as the next major constituent
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C22F1/06—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of magnesium or alloys based thereon

Definitions

  • the invention relates to a method for improving the strength and strain fatigue life of a magnesium alloy, in particular to a method for improving the strength and fatigue performance of an AQ80M magnesium alloy through a composite process of multi-directional forging and cooling rolling, and belongs to the technical field of magnesium alloy deformation processing .
  • magnesium alloys Compared with traditional metal structural materials, magnesium alloys have large reserves, low density (about 2/3 of aluminum, 1/4 of iron), high specific strength and specific stiffness, good electromagnetic shielding performance, and good seismic and noise reduction performance. Easy to recycle without pollution, known as "21st Century Green Engineering Materials”. Due to these outstanding advantages, magnesium alloys have important application value and broad application prospects in the fields of transportation, aerospace and defense and military industries.
  • AQ80M magnesium alloy is a new type of deformed magnesium alloy with low cost and simple casting process. It is a magnesium alloy material suitable for wide application. Compared with traditional die-casting magnesium alloys, magnesium alloys can not only produce components with various shapes and sizes after deformation processing, but also eliminate structural defects in the casting and improve mechanical properties. However, compared with traditional materials such as aluminum alloy and steel, the problems of AQ80M magnesium alloy's low strength, narrow thermal deformation temperature range, and large room temperature deformation resistance have become the technical bottlenecks that restrict its wide-scale application.
  • a common method to improve the strength of AQ80M magnesium alloy is to use its high solid-solubility Al atoms for aging treatment.
  • the aging precipitated Mg17Al12 phase of AQ80M magnesium alloy has a larger size and its inertial plane is parallel to the (0001) plane of the matrix, which strengthens the effect. not ideal.
  • a large number of aging precipitates will hinder the movement of dislocations, leading to a significant decline in the plasticity and fatigue resistance of the material.
  • aircraft and auto parts are often subject to cyclic loading, so fatigue is also one of the main reasons for the failure of engineering components. Therefore, in order to ensure the durability and safety and reliability of such material parts during use, how to improve the strength of magnesium alloys while ensuring their fatigue resistance has become an urgent problem in the industry.
  • this patent proposes innovatively using the process of multi-directional forging and cooling and final rolling, and through reasonable setting of deformation parameters, a yield strength of 280 MPa and a tensile strength of ⁇ 350 MPa have been successfully prepared.
  • AQ80M magnesium alloy with fatigue life ⁇ 104 times when the total strain amplitude is 0.3% and fatigue life ⁇ 2200 times when the total strain amplitude is 0.5%.
  • the purpose of the present invention is to provide a method for comprehensively improving the strength and strain fatigue performance of AQ80M deformed magnesium alloy in view of the insufficient technical strength of Mg-Al-Zn series magnesium alloy and the conventional strengthening method to greatly reduce plasticity and fatigue performance.
  • the invention obtains a deformed structure with small grain size and no dynamic precipitation phase by controlling the process parameters of multi-directional forging and cooling rolling deformation of AQ80M magnesium alloy. Under the premise of ensuring higher strength, the dislocation slip resistance during cyclic plastic deformation is reduced, and the material's strain fatigue performance is improved, so as to meet the actual production requirements of aerospace and automotive parts for safe and reliable magnesium alloy materials.
  • AQ80M magnesium alloy ingot prepared by semi-continuous casting method the alloy composition is (wt.%): Al: 7.5 to 9.0%, Ag: 0.02 to 0.80%, Zn: 0.35 to 0.55%, Mn: 0.05 to 0.20% , RE: 0.01 ⁇ 0.10%, Ca: 0.001 ⁇ 0.020%, Fe ⁇ 0.02%, Si ⁇ 0.05%, Cu ⁇ 0.02%, Ni ⁇ 0.001%, and the rest are Mg;
  • Two-stage homogenization annealing In order to eliminate casting stress and reduce or eliminate non-equilibrium precipitated phases, the ingot is first kept at 240-270 ° C for 10-12 hours, and then heated to 390-420 ° C for 40-48 hours;
  • the multi-directional forging and sintering can eliminate casting defects and improve the alloy structure, and the obtained weakly textured ingot provides a guarantee for subsequent rolling forming. At the same time, controlling the forging pass will not reduce the temperature too much, avoiding the problems of grain growth and low production efficiency caused by intermediate annealing;
  • High-temperature initial rolling After multi-directional forging, the ingot is kept at 380 ⁇ 430 °C for 1 ⁇ 3h, and then double-rolled. The rolling speed is 0.2 ⁇ 0.8 m / s. There are 6 passes in total. It is 10% ⁇ 25%, and it is re-annealed between each pass. The annealing temperature is 380 ⁇ 420 °C, and the annealing time is 5 ⁇ 45 min.
  • Cooling and final rolling 6 sheets of the first rolling are quickly air-cooled to 150-330 ° C, the final rolling reduction is 5% to 25%, the rolling speed is 0.2 to 0.8 m / s, and the water is cooled immediately after the final rolling. Quenched.
  • the ingot is maintained at 390 to 410 ° C for 3 to 6 hours.
  • the forging pass reduction in step 3 is 15% to 25%, and there is no intermediate annealing treatment between passes.
  • the high-temperature initial rolling temperature described in step 4 is 390 to 410 ° C, the rolling reduction is 10% to 20%, the temperature between the passes is 390 to 410 ° C, and the annealing time is 5 to 15 minutes.
  • the final rolling temperature in step 5 is 200-330 ° C, and the final rolling reduction is 10-20%.
  • the present invention proposes a deformation process that can practically improve the strength and strain fatigue performance of AQ80M magnesium alloy, in which processing methods such as multi-directional forging and blooming and cooling rolling can be achieved with traditional equipment, and the related processing technology is also very Mature and easy to operate, suitable for large-scale industrial production.
  • High temperature rolling after forging and forging can effectively avoid the formation of Mg17Al12 dynamic precipitation phase which is detrimental to the plasticity and fatigue properties of the rolled plate, and improve the processing plasticity of the material in the final rolling deformation. Selecting a reasonable preliminary rolling process can improve the material's formability and mechanical properties.
  • the initial 6 passes of rolling used a higher deformation temperature, so that during the rolling process of AQ80M magnesium alloy, a variety of deformation mechanisms can participate in the deformation, making full use of the high-temperature plasticity of the material, and ensuring a large total amount of plastic deformation.
  • the initial rolling temperature is too high, the grains are not easy to refine, which reduces the mechanical properties of the material.
  • the annealing heat preservation of 5 to 15 minutes between intermediate passes can effectively eliminate work hardening, and avoid excessive growth of deformed grains caused by too long heat preservation time, ensuring the quality of the preliminary rolled sheet, and the subsequent final rolling forming. Provides a good foundation.
  • the final rolling deformation process directly affects the grain size, phase composition, degree of work hardening, and texture of the obtained alloy products, and then affects the strength and fatigue properties of the alloy.
  • the final pass uses cooling rolling, and the deformation temperature is controlled at 150-350 °C, which can further effectively refine the grains, preserve the work hardening and texture strengthening of the material, and increase the strength of the rolled plate.
  • grain refinement can inhibit the formation of twins, effectively reduce the accumulation of irreversible plastic deformation of the alloy during cyclic deformation, and improve the fatigue performance of the material.
  • the dynamic precipitation phase is too late during low temperature rapid rolling forming, which can also reduce the obstacles of reciprocating slip displacement and fatigue damage accumulation of the alloy during fatigue deformation, thereby improving the strain fatigue life of the AQ80M magnesium alloy.
  • FIG. 1 (a) is an as-cast metallographic structure diagram of the AQ80M magnesium alloy in Example 1.
  • FIG. 1 (a) is an as-cast metallographic structure diagram of the AQ80M magnesium alloy in Example 1.
  • FIG. 1 (b) is the metallographic structure of the AQ80M magnesium alloy after multi-directional forging and blooming in Example 1.
  • FIG. 1 (b) is the metallographic structure of the AQ80M magnesium alloy after multi-directional forging and blooming in Example 1.
  • FIG. 1 (c) is a metallographic structure diagram of the AQ80M magnesium alloy after multi-directional forging, slab rolling, and cooling in Example 1.
  • FIG. 1 (c) is a metallographic structure diagram of the AQ80M magnesium alloy after multi-directional forging, slab rolling, and cooling in Example 1.
  • FIG. 2 is a metallographic structure diagram of direct low-temperature rolling after multidirectional forging in Comparative Example 2.
  • FIG. 2 is a metallographic structure diagram of direct low-temperature rolling after multidirectional forging in Comparative Example 2.
  • FIG. 3 is an average stress-lifetime curve graph of the AQ80M magnesium alloy in Example 1 after cooling and final rolling.
  • FIG. 4 is a graph of the average stress-life curve of the AQ80M magnesium alloy in Comparative Example 2.
  • FIG. 4 is a graph of the average stress-life curve of the AQ80M magnesium alloy in Comparative Example 2.
  • Fig. 1 (a) the as-cast metallographic structure of AQ80M is mainly composed of ⁇ -Mg matrix and coarse Mg 17 Al 12 dendrites.
  • the semi-continuously cast AQ80M magnesium alloy ingot was subjected to a two-stage homogenization treatment at 250 ° C / 10h + 420 ° C / 40h, and then air-cooled to room temperature, and then descaled to form a cube sample.
  • the ingot was placed in an annealing furnace at 410 ° C for 4 hours, and the upper and lower flat anvils were heated to 300 ° C.
  • the rectangular parallelepiped sample was subjected to a fire forging on an oil press: the sample length was Z, and the rest The two directions are arbitrarily Y and X directions, and they are compressed in the order of ZYXZYX.
  • the reduction speed is 200 ⁇ 400 mm / min, and the pass reduction is 15% ⁇ 25%.
  • the forged billet was cut into 40 mm ⁇ 80 mm ⁇ 180 mm plates, and after being held at 400 ° C for 2.5 hours, the rolls were rolled 6 times in advance. The rolls were preheated to 200 ° C in advance, and the reduction of the passes was 10% -20%. In each pass, the furnace is annealed at an annealing temperature of 400 ° C and an annealing time of 10 minutes. After 6 passes of the preliminary rolling, the rolled sheet is rapidly cooled to 300 ° C for the final rolling treatment, and the rolling reduction is 17%, and the water-cooled quenching is performed immediately after the completion of the final rolling. Its mechanical properties are shown in Table 1.
  • FIG. 1 (A, b, and c) in Figure 1 are the as-cast metallographic structure of the AQ80M magnesium alloy, the metallographic structure after multidirectional forging and blooming, and the metallographic structure after cooling and rolling.
  • the average stress-life curve of AQ80M magnesium alloy after cooling and final rolling is shown in Figure 3.
  • the semi-continuously cast AQ80M magnesium alloy ingot was subjected to a two-stage homogenization treatment at 250 ° C / 10h + 420 ° C / 40h, and then air-cooled to room temperature, and then descaled to form a cube sample.
  • the ingot was placed in an annealing furnace and heated at 400 ° C for 4 hours.
  • the upper and lower flat anvils were heated to 280 ° C.
  • the rectangular parallelepiped sample was subjected to one-shot forging on an oil press: the sample length was Z, and the rest
  • the two directions are arbitrarily Y and X directions, and they are compressed in the order of ZYXZYX.
  • the reduction speed is 200 ⁇ 400 mm / min, and the pass reduction is 15% ⁇ 25%.
  • the forged billet was cut into 40 mm ⁇ 80 mm ⁇ 180 mm slabs. After holding at 410 ° C for 2 hours, the rolls were rolled 6 times in advance. The rolls were preheated to 200 ° C in advance. The reduction of the passes was 10% to 20%.
  • the annealing temperature is 410 °C and the annealing time is 5 minutes. After 6 passes of the initial rolling, the rolled sheet is rapidly cooled to 280 ° C for the final rolling treatment, and the rolling reduction is 15%, and the water-cooled quenching is performed immediately after the completion of the final rolling. Its mechanical properties are shown in Table 1.
  • the semi-continuously cast AQ80M magnesium alloy ingot was subjected to a two-stage homogenization treatment at 250 ° C / 10h + 420 ° C / 40h, and then air-cooled to room temperature, and then descaled to form a cube sample.
  • the ingot was placed in an annealing furnace and heated at 400 ° C for 4 hours.
  • the upper and lower flat anvils were heated to 280 ° C.
  • the rectangular parallelepiped sample was subjected to one-shot forging on an oil press: the sample length was Z, and the rest
  • the two directions are arbitrarily Y and X directions, and they are compressed in the order of ZYXZYX.
  • the reduction speed is 200 ⁇ 400 mm / min, and the pass reduction is 15% ⁇ 25%.
  • the forged billet was cut into 40 mm ⁇ 80 mm ⁇ 180 mm plates, and after being held at 410 ° C for 2.5 hours, it was rolled in 6 passes with twin rolls. The rolls were preheated to 200 ° C in advance, and the rolling reduction was 10% to 20%.
  • the annealing temperature is 410 °C and the annealing time is 5 minutes. After 6 passes of the initial rolling, the rolled sheet is rapidly cooled to 250 ° C for the final rolling treatment, and the rolling reduction is 15%. After the completion of the final rolling, water cooling and quenching are performed immediately.
  • Table 1 The mechanical properties are shown in Table 1.
  • the semi-continuously cast AQ80M magnesium alloy ingot was subjected to a two-stage homogenization treatment at 250 ° C / 10h + 420 ° C / 40h, and then air-cooled to room temperature, and then descaled to form a cube sample.
  • the ingot was placed in an annealing furnace for heating at 410 ° C for 4 hours, and the upper and lower flat anvils were heated to 280 ° C.
  • the rectangular parallelepiped sample was subjected to a fire forging on an oil press: the sample length was Z, and the rest
  • the two directions are arbitrarily Y and X directions, and they are compressed in the order of ZYXZYX.
  • the pass reduction is 15% to 25%. Water-quenched immediately after multidirectional forging. Its mechanical properties are shown in Table 1.
  • the semi-continuously cast AQ80M magnesium alloy ingot was subjected to a two-stage homogenization treatment at 250 ° C / 10h + 420 ° C / 40h, and then air-cooled to room temperature, and then descaled to form a cube sample.
  • the ingot was placed in an annealing furnace and heated at 400 ° C for 4 hours.
  • the upper and lower flat anvils were heated to 280 ° C, and the rectangular parallelepiped sample was subjected to a fire forging on an oil press.
  • the two directions are arbitrarily Y and X directions, and they are compressed in the order of ZYXZYX.
  • the pass reduction is 15% to 25%.
  • the forged billet was cut into 40 mm ⁇ 80 mm ⁇ 180 mm slabs. After being held at 300 ° C for 2 hours, it was rolled with two rolls. The rolls were preheated to 200 ° C in advance, and the pass reduction was 15%. , The annealing temperature is 300 ° C, the annealing time is 10 minutes, and the water cooling quenching is performed immediately after the 6 passes of rolling. Its mechanical properties are shown in Table 1.
  • the metallographic structure of direct low-temperature rolling is shown in Figure 2, and the average stress-life curve of AQ80M magnesium alloy is shown in Figure 4.
  • Example 1 281 281 356 356 16.1 16.1 13080 2465 2465
  • Example 2 285 285 351 351 14.9 14.9 11992 2357 2357

Abstract

本发明公开了一种提高AQ80M镁合金强度和应变疲劳寿命的方法，包括如下步骤:将AQ80M半连续铸造锭坯均匀化退火后进行多向锻造开坯，将所得的锻造坯料在380～430℃高温初轧后降温至150～330℃终轧成形。本发明充分发挥了AQ80M镁合金的高温塑性优势，提高合金成形性，又避免动态析出造成的材料塑性及疲劳性能大幅下降；同时通过快速冷却降低终轧温度，可有效细化晶粒尺寸，提高材料强度和应变疲劳寿命。本发明操作工艺简单易行，所制备的AQ80M镁合金板材屈服强度≥280MPa，抗拉强度≥350MPa，外加总应变幅为0.3%时疲劳寿命≥10 4次，外加总应变幅为0.5%时疲劳寿命≥2200次。

Description

一种提高AQ80M镁合金强度和应变疲劳寿命的方法 技术领域
本发明涉及一种提高镁合金的强度和应变疲劳寿命的方法，具体涉及一种通过多向锻造与降温轧制的复合工艺提高AQ80M镁合金强度和疲劳性能的方法，属于镁合金变形加工技术领域。
 背景技术
与传统的金属结构材料相比，镁合金储量大，密度低（约为铝的2/3，铁的1/4），比强度、比刚度高，电磁屏蔽性能和抗震减噪性能好，且易于回收无污染，被誉为“21世纪绿色工程材料”。由于这些突出的优点，镁合金在交通、航空航天及国防军工等领域有着重要的应用价值和广阔的应用前景。
AQ80M镁合金作为一种新型变形镁合金，成本低廉且铸造工艺简单，是比较适合于广泛应用的镁合金材料。相比于传统压铸镁合金，镁合金变形加工后不仅可以制备形状尺寸多样化的构件，还可以消除铸件中的组织缺陷，提高力学性能。然而相较于铝合金、钢铁等传统材料，AQ80M镁合金强度不高、热变形温度范围窄、室温变形抗力大等问题成为了制约其大范围应用的技术瓶颈。
提高AQ80M镁合金强度的常用方法是利用其高固溶度的Al原子进行时效处理，但AQ80M镁合金时效析出的Mg17Al12相尺寸较大且其惯析面平行于基体的（0001）面，强化效果不理想。同时大量的时效析出相会阻碍位错运动，导致材料的塑性及抗疲劳性能大幅度下降。在实际服役的过程中，除了静态加载损伤外，飞机汽车零部件还经常受到循环载荷的作用，因而疲劳也是工程构件失效的主要原因之一。因此，为确保此类材料零部件在使用过程中的持久性及安全可靠性，如何在提高镁合金的强度的同时还保证其抗疲劳性能成为了业内急需解决的难题。
 技术问题
针对航空航天及交通运输领域的实际生产需求，本专利创新性的提出利用多向锻造与降温终轧复合的工艺，通过合理设置变形参数，成功制备出了屈服强度≥280MPa，抗拉强度≥350MPa，外加总应变幅为0.3%时疲劳寿命≥104次，外加总应变幅为0.5%时疲劳寿命≥2200次的AQ80M镁合金。
 技术解决方案
本发明的目的在于针对Mg-Al-Zn系镁合金强度不高且常规强化方式大幅降低塑性和疲劳性能的技术不足，提供一种综合改善AQ80M变形镁合金强度和应变疲劳性能的方法。本发明通过控制AQ80M镁合金多向锻造及降温轧制变形工艺参数，获得了晶粒尺寸较小，无动态析出相的变形组织。在保证较高强度的前提下，减小循环塑性变形过程中位错滑移抗力，提高材料应变疲劳性能，以满足航空航天及汽车零部件对镁合金材料安全可靠的实际生产需求。
本发明具体的实施方案如下:
1.半连续铸造方法制备的AQ80M镁合金锭坯，合金成分为（wt. %）: Al:7.5～9.0%、Ag :0.02～0.80%、Zn :0.35～0.55%、Mn: 0.05～0.20%、RE:0.01～0.10%、Ca:0.001～0.020%、Fe≤0.02%、Si≤0.05%、Cu≤0.02%、Ni≤0.001%，其余为Mg；
2.双级均匀化退火:为消除铸造应力，减少或消除非平衡析出相，铸锭在240～270℃先保温10～12h，随后升温至390～420℃保温40～48h；
3.均匀化退火后车皮，下料，多向锻造开坯。锭坯先在380～420 ℃下保温2～10h，保温同时加热上下平砧至250～350℃。在油压机上进行多向锻造，以坯料最长向为Z向，其余垂直两向为任意Y、X向，按Z-Y-X-Z-X-Y顺序进行六道次压缩变形，压下速度为200～400 mm/min，单道次压下量为10%-30%。通过多向锻造开坯能消除铸造缺陷，改善合金组织，得到的弱织构锭坯为后续轧制成形提供了保证。同时控制好锻造道次不会使温度下降太多，避免了中间退火造成的晶粒长大，生产效率低等问题；
4.高温初轧:多向锻造后锭坯在380～430℃保温1～3h后，双辊轧制，轧制速度为 0.2～0.8 m/s， 共6个道次，道次压下量为10%～25%，每道次之间回炉退火，退火温度为380～420℃，退火时间5～45 min。
5.降温终轧:将初轧6道次的板材迅速空冷至150-330℃，终轧压下量为5%～25%，轧制速度为0.2～0.8 m/s，终轧结束立即水冷淬火。
步骤3所述的多向锻造前，锭坯经390～410 ℃保温3～6 h。
步骤3所述锻造道次压下量为15%～25%，道次间无中间退火处理。
步骤4所述的高温初轧温度为390～410℃，道次压下量为10%～20%，道次之间回炉温度为390～410℃，退火时间5～15 min。
步骤5所述的终轧温度为200～330℃，终轧压下量为10～20%。
 有益效果
与现有技术相比，本发明的优点如下：
1. 本发明提出了一种能切实可行提高AQ80M镁合金的强度和应变疲劳性能的变形工艺，其中多向锻造开坯和降温轧制等加工方法用传统设备即可实现，相关加工技术也很成熟易于操作，适用于大范围工业生产。
2. 采用高温多向锻造开坯，消除了原始铸锭中的组织缺陷，镁合金在高温锻造过程中发生完全动态再结晶，不仅起到软化作用，还改善了合金组织，细化晶粒。此外，多道次的换向锻造，避免了变形过程中形成强烈的基面织构，为后续轧制成形提供了塑性较好，组织均匀的坯料，极大的降低了后续轧制变形过程中板材开裂的风险。
3. 锻造开坯后先进行高温轧制能够有效避免有害于轧板塑性跟疲劳性能的Mg17Al12动态析出相的形成，提高材料在终轧变形中的加工塑性。选用合理的初轧工艺，即可改善材料的成形性能，又可以提高力学性能。初始6道次的轧制采用了较高的变形温度，使AQ80M镁合金轧制过程中有多种变形机制能参与变形，充分发挥了材料的高温塑性，保证较大的总的塑性变形量。初始轧制温度过高，晶粒不容易细化，降低材料的力学性能，初始轧制温度过低，会增大板材开裂风险。同时，中间道次之间5～15 min的退火保温既能有效消除加工硬化，又避免了保温时间过长造成变形晶粒过分长大，保证了初轧板材的质量，为后续的终轧成形提供了良好的基础。
4. 终轧变形工艺直接影响获得的合金产品的晶粒尺寸、相组成、加工硬化程度以及织构，进而影响合金的强度及疲劳性能。最终道次采用降温轧制，将变形温度控制在150～350 ℃，能进一步有效细化晶粒，保存材料的加工硬化和织构强化，使轧板强度升高。同时，晶粒细化能抑制孪晶的形成，有效减少了合金在循环变形过程中不可逆塑性变形的累积，改善材料疲劳性能。此外，低温快轧成形过程中动态析出相来不及析出，也能降低疲劳变形过程中往复滑移位错的阻碍及合金的疲劳损伤累积，从而提高了AQ80M镁合金的应变疲劳寿命。
 附图说明
图1（a）是实施例1中AQ80M镁合金铸态金相组织图。
图1（b）是实施例1中AQ80M镁合金多向锻造开坯后的金相组织图。
图1（c）是实施例1中AQ80M镁合金多向锻造开坯降温轧制后的金相组织图。
图2是对比例2中多向锻造后直接低温轧制的金相组织图。
图3是实施例1中的AQ80M镁合金降温终轧后的平均应力-寿命曲线图。
图4是对比例2中AQ80M镁合金平均应力-寿命曲线图。
从图1（a）中可以看出AQ80M铸态金相组织主要由α-Mg基体和粗大的Mg 17Al 12枝晶组成。
从图一（b）中可知，固溶处理及高温多向锻造开坯后，Mg 17Al 12相完全溶解，晶粒得到细化且组织变得等轴均匀，同时消除了铸造过程中的组织缺陷，为后续轧制成形提供了优质的坯料，降低了轧制变形过程中板材开裂的风险。
从图1（c）中可以看出 AQ80M镁合金降温轧制后晶粒进一步得到细化，同时组织中形成了大量孪晶和细小的再结晶晶粒构成的剪切带，晶粒细化有利于合金强度和塑性的提高。同时晶粒尺寸减小，抑制了合金在应变控制变形过程中孪晶的形成，降低了循环变形过程中不可逆塑性变形的累积，有利于疲劳寿命的提高。
从图2的对比例2中直接低温轧制的金相组织图可以看出：轧制后，AQ80M镁合金的晶粒虽然得到了细化，但是持续低温下Al原子固溶度下降，在变形过程中形成了大量球状的Mg 17Al 12动态析出相。这种动态析出相与镁基体非共格且在塑性变形过程中容易阻碍位错运动造成应力集中，使得基体与第二相分离形成微裂纹，从而极大的降低了合金的塑性和低周疲劳寿命。
从图3的AQ80M镁合金降温终轧后的平均应力-寿命曲线图可以观察到当外加总应变幅为0.3%时，合金的疲劳寿命为12838周次，初始平均应力幅为111.3MPa，当外加总应变幅为0.5%时，合金的疲劳寿命为2221次，初始平均应力幅为160.7MPa。
从图4的对比例2中直接轧制的AQ80M镁合金平均应力-寿命曲线图可知到当外加总应变幅为0.3%时，合金疲劳寿命为6237周次，初始平均应力幅为107.1MPa，当外加总应变幅为0.5%时，合金的疲劳寿命为1469次，初始平均应力幅为153.7MPa。说明降温轧制这种工艺能够有效的改善合金的强度和低周疲劳寿命。
 本发明的最佳实施方式
在此处键入本发明的最佳实施方式描述段落。
 本发明的实施方式
下面给出的实施案例拟对本发明作进一步阐述说明，但以下实例并非是对本发明的保护范围的限制，在本发明的构思前提下，相关领域技术人员依据本发明的技术实质所做的任何非本质的调整与改进，均属于本发明技术方案的保护范围。
实施例1
半连续铸造的AQ80M镁合金锭坯，经250℃/10h + 420℃/40h双级均匀化处理后空冷至室温，车去氧化皮加工成长方体试样。多向锻造前，锭坯放入退火炉中410℃下加热保温4h，加热上下平砧至300℃，在油压机上对长方体试样进行一火锻造开坯:以试样长向为Z，其余两向任意为Y、X向，按Z-Y-X-Z-Y-X顺序压缩，压下速度为200～400 mm/min，道次压下量为15%～25%。将锻造坯料切成40 mm × 80 mm × 180 mm板块，400℃保温2.5 h后，双辊轧制6个道次，轧辊提前预热至200℃，道次压下量为10%-20%，每道次间回炉退火，退火温度为400℃，退火时间10 min。初轧6道次后，将轧板快速降温至300℃终轧处理，道次压下量为17%，终轧完成后立即水冷淬火。其力学性能见表一。图1中（a，b，c）分别是AQ80M镁合金铸态金相组织图，多向锻造开坯后的金相组织图以及降温轧制后的金相组织图。AQ80M镁合金降温终轧后的平均应力-寿命曲线图如图3所示。
实施例2
半连续铸造的AQ80M镁合金锭坯，经250℃/10h + 420℃/40h双级均匀化处理后空冷至室温，车去氧化皮加工成长方体试样。多向锻造前，锭坯放入退火炉中400℃下加热保温4h，加热上下平砧至280℃，在油压机上对长方体试样进行一火锻造开坯:以试样长向为Z，其余两向任意为Y、X向，按Z-Y-X-Z-Y-X顺序压缩，压下速度为200～400 mm/min，道次压下量为15%～25%。将锻造坯料切成40 mm × 80 mm × 180 mm板块，410℃保温2 h后，双辊轧制6个道次，轧辊提前预热至200℃，道次压下量为10%～20%，每道次间回炉退火，退火温度为410℃，退火时间5 min。初轧6道次后，将轧板快速降温至280℃终轧处理，道次压下量为15%，终轧完成后立即水冷淬火。其力学性能见表一。
实施例3
半连续铸造的AQ80M镁合金锭坯，经250℃/10h + 420℃/40h双级均匀化处理后空冷至室温，车去氧化皮加工成长方体试样。多向锻造前，锭坯放入退火炉中400℃下加热保温4h，加热上下平砧至280℃，在油压机上对长方体试样进行一火锻造开坯:以试样长向为Z，其余两向任意为Y、X向，按Z-Y-X-Z-Y-X顺序压缩，压下速度为200～400 mm/min，道次压下量为15%～25%。将锻造坯料切成40 mm × 80 mm × 180 mm板块， 410℃保温2.5 h后，双辊轧制6个道次，轧辊提前预热至200℃，道次压下量为10%～20%，每道次间回炉退火，退火温度为410℃，退火时间5 min。初轧6道次后，将轧板快速降温至250℃终轧处理，道次压下量为15%，终轧完成后立即水冷淬火，其力学性能见表一
对比例1
半连续铸造的AQ80M镁合金锭坯，经250℃/10h + 420℃/40h双级均匀化处理后空冷至室温，车去氧化皮加工成长方体试样。多向锻造前，锭坯放入退火炉中410℃下加热保温4h，加热上下平砧至280℃，在油压机上对长方体试样进行一火锻造开坯:以试样长向为Z，其余两向任意为Y、X向，按Z-Y-X-Z-Y-X顺序压缩，道次压下量为15%～25%。多向锻造完毕后立即水冷淬火。其力学性能见表一。
对比例 2
半连续铸造的AQ80M镁合金锭坯，经250℃/10h + 420℃/40h双级均匀化处理后空冷至室温，车去氧化皮加工成长方体试样。多向锻造前，锭坯放入退火炉中400℃下加热保温4h，加热上下平砧至280℃，在油压机上对长方体试样进行一火锻造开坯:以试样长向为Z，其余两向任意为Y、X向，按Z-Y-X-Z-Y-X顺序压缩，道次压下量为15%～25%。将锻造坯料切成40 mm × 80 mm × 180 mm板块，300℃保温2 h后，双辊轧制，轧辊提前预热至200℃，道次压下量为15%，每道次间回炉退火，退火温度为300℃，退火时间10 min，6道次轧制完毕后立即水冷淬火。其力学性能见表一。直接低温轧制的金相组织图如图2所示，AQ80M镁合金平均应力-寿命曲线图如图4所示。
表1 实施例及对比例中AQ80M镁合金力学性能的对比。
实例     屈服强度   抗拉强度   延伸率      疲劳寿命     疲劳寿命
               / MPa         / MPa         / %          N f(±0.3%)     N f(±0.5%) 
实施例1      281         356         16.1            13080             2465
实施例2      285         351          14.9             11992             2357
实施例3      290         362          14.5            10335            2232
对比例1      155         285           15               8656             1694
对比例2      268          330           6.5              6137              1290
 工业实用性
在此处键入工业实用性描述段落。
 序列表自由内容
在此处键入序列表自由内容描述段落。

Claims (11)

  1. 一种提高AQ80M镁合金强度和应变疲劳寿命的方法，其特征在于，包括以下具体步骤:
    A:采用半连续铸造方法制备镁合金铸锭，双级均匀化热处理后，空冷至室温，车氧化皮，得到镁合金坯料；
    B:多向锻造开坯：将均匀化处理的镁合金锭坯切割成长方体试样，在380～420℃下保温2～10h，同时预热上下平砧，温度为250～350℃；保温结束后，在油压机上进行多向自由锻造，以长方体的长边为Z向，其余垂直两向为任意Y、X向，以Z-Y-X顺序为一个循环进行点动式压缩变形，锻造道次压下量为10%～30%，直接锻造6道次后空冷，道次间无回炉退火处理；
    C:高温初轧:将多向锻造后的坯料在380～430℃保温1～3h后，双辊轧制，轧辊提前预热至150～300℃，一共轧制6个道次，道次压下量为10%～25%，每道次之间回炉退火，退火温度为380～430℃，退火时间5～45 min；
    D:降温终轧:将初轧6道次的板材迅速空冷至150～330℃，终轧压下量为5%～25%，终轧道次结束后立即水冷淬火。
  2. 根据权利要求1所述的一种提高AQ80M镁合金强度和应变疲劳寿命的方法，其特征在于: AQ80M镁合金应变疲劳寿命测试的实验控制模式为应变控制，外加总应变幅为0.3%和0.5%，应变比为-1，加载频率为0.3～1HZ。
  3. 根据权利要求1所述的一种提高AQ80M镁合金强度和应变疲劳寿命的方法，其特征在于:步骤B中，下压速度为200～400 mm/min。
  4. 根据权利要求3所述的一种提高AQ80M镁合金强度和应变疲劳寿命的方法，其特征在于:B步骤所述的多向锻造开坯是将坯料在390～410℃保温3～6h，锻造6个道次，单道次压下量为15%～25%，道次间无中间退火处理。
  5. 根据权利要求1所述的一种提高AQ80M镁合金强度和应变疲劳寿命的方法，其特征在于:C步骤中所述的高温初轧是将轧辊提前预热至150-250℃。
  6. 根据权利要求1所述的一种提高AQ80M镁合金强度和应变疲劳寿命的方法，其特征在于: 步骤 C中，轧制速度为 0.2～0.8 m/s。
  7. 根据权利要求6所述的一种提高AQ80M镁合金强度和应变疲劳寿命的方法，其特征在于:C步骤所述的高温初轧温度为390～410℃，道次压下量为10%～20%，每道次之间回炉退火，退火温度为390～410℃，退火时间5～15 min。
  8. 根据权利要求1所述的一种提高AQ80M镁合金强度和应变疲劳寿命的方法，其特征在于:步骤D中，轧制速度为0.2～0.8 m/s。
  9. 根据权利要求8所述的一种提高AQ80M镁合金强度和应变疲劳寿命的方法，其特征在于:D步骤所述的终轧温度为200～330℃，终轧压下量为10～20%。
  10. 根据权利要求1-9任意一项所述的一种提高AQ80M镁合金强度和应变疲劳寿命的方法，其特征在于: 所述的AQ80M镁合金成分质量百分比为: Al:7.5～9.0%、Ag:0.02～0.80%、Zn:0.35～0.55%、Mn:0.05～0.20%、RE:0.01～0.10%、Ca:0.001～0.020%、Fe≤0.02%、Si≤0.05%、Cu≤0.02%、Ni≤0.001%，其余为Mg。
  11. 根据权利要求10所述的一种提高AQ80M镁合金强度和应变疲劳寿命的方法，其特征在于:低温终轧后AQ80M镁合金板材屈服强度≥280MPa，抗拉强度≥350MPa，外加总应变幅为0.3%时疲劳寿命≥10 4次，外加总应变幅为0.5%时疲劳寿命≥2200次。
     
     
PCT/CN2019/104796 2018-09-09 2019-09-06 一种提高aq80m镁合金强度和应变疲劳寿命的方法 WO2020048539A1 (zh)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN201811047415.9A CN109022975B (zh) 2018-09-09 2018-09-09 一种提高aq80m镁合金强度和应变疲劳寿命的方法
CN201811047415.9 2018-09-09

Publications (1)

Publication Number Publication Date
WO2020048539A1 true WO2020048539A1 (zh) 2020-03-12

Family

ID=64620840

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2019/104796 WO2020048539A1 (zh) 2018-09-09 2019-09-06 一种提高aq80m镁合金强度和应变疲劳寿命的方法

Country Status (2)

Country Link
CN (1) CN109022975B (zh)
WO (1) WO2020048539A1 (zh)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109022975B (zh) * 2018-09-09 2020-03-17 中南大学 一种提高aq80m镁合金强度和应变疲劳寿命的方法
CN111678821A (zh) * 2020-06-23 2020-09-18 山东大学 基于高温合金加工表面完整性的低周疲劳寿命预测方法
CN111944958B (zh) * 2020-07-26 2022-09-20 杨军 一种高强度块体316l不锈钢的制备方法
CN112481536B (zh) * 2020-11-04 2022-12-09 航天科工(长沙)新材料研究院有限公司 一种镁合金厚板及其制备方法
CN112589024B (zh) * 2020-11-04 2023-01-17 航天科工(长沙)新材料研究院有限公司 一种镁合金锻件及其制备方法
CN115323296B (zh) * 2022-08-25 2024-03-12 中铝洛阳铜加工有限公司 一种宽幅镁合金板材的加工方法

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3680818B2 (ja) * 2002-05-23 2005-08-10 住友金属工業株式会社 マグネシウム合金薄板の製造方法及びその製造装置
WO2006003833A1 (ja) * 2004-06-30 2006-01-12 Sumitomo Electric Industries, Ltd. マグネシウム合金材の製造方法
CN102321836A (zh) * 2011-10-12 2012-01-18 中南大学 一种高强耐热镁合金薄板的制备方法
CN106734205A (zh) * 2017-02-07 2017-05-31 吉林大学 一种短流程轧制制备超塑性镁合金的方法
CN106944799A (zh) * 2017-03-23 2017-07-14 中南大学 Aq80m镁合金环形件挤锻轧集成工艺
CN107130197A (zh) * 2017-05-25 2017-09-05 西安航空学院 一种超细晶az80镁合金的形变热处理方法
CN107142431A (zh) * 2017-06-01 2017-09-08 哈尔滨工业大学 一种az80a镁合金锻坯挤压多向锻造复合工艺提高强度的方法
CN109022975A (zh) * 2018-09-09 2018-12-18 中南大学 一种提高aq80m镁合金强度和应变疲劳寿命的方法

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4139841B2 (ja) * 2004-09-30 2008-08-27 能人 河村 鋳造物及びマグネシウム合金の製造方法
JP4939841B2 (ja) * 2006-05-31 2012-05-30 三井金属鉱業株式会社 マグネシウム合金鍛造品及びその製造方法
CN103909382B (zh) * 2014-01-18 2016-01-20 中南大学 一种大直径中强耐热镁合金厚壁筒形件成形工艺
CN105648370B (zh) * 2016-02-03 2017-07-11 中南大学 一种提高稀土镁合金铸件力学性能的热处理工艺
CN106929724B (zh) * 2017-03-23 2018-08-14 中南大学 Aq80m镁合金宽厚板热挤压工艺

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3680818B2 (ja) * 2002-05-23 2005-08-10 住友金属工業株式会社 マグネシウム合金薄板の製造方法及びその製造装置
WO2006003833A1 (ja) * 2004-06-30 2006-01-12 Sumitomo Electric Industries, Ltd. マグネシウム合金材の製造方法
CN102321836A (zh) * 2011-10-12 2012-01-18 中南大学 一种高强耐热镁合金薄板的制备方法
CN106734205A (zh) * 2017-02-07 2017-05-31 吉林大学 一种短流程轧制制备超塑性镁合金的方法
CN106944799A (zh) * 2017-03-23 2017-07-14 中南大学 Aq80m镁合金环形件挤锻轧集成工艺
CN107130197A (zh) * 2017-05-25 2017-09-05 西安航空学院 一种超细晶az80镁合金的形变热处理方法
CN107142431A (zh) * 2017-06-01 2017-09-08 哈尔滨工业大学 一种az80a镁合金锻坯挤压多向锻造复合工艺提高强度的方法
CN109022975A (zh) * 2018-09-09 2018-12-18 中南大学 一种提高aq80m镁合金强度和应变疲劳寿命的方法

Also Published As

Publication number Publication date
CN109022975B (zh) 2020-03-17
CN109022975A (zh) 2018-12-18

Similar Documents

Publication Publication Date Title
WO2020048539A1 (zh) 一种提高aq80m镁合金强度和应变疲劳寿命的方法
CN108300918B (zh) 一种具有高室温成形性能含钙稀土镁合金板材及制备方法
CN102644039B (zh) 半导体设备用高品质6061铝合金锻件制备方法
CN107779706B (zh) 一种铝锂合金及挤压方法
CN113061820B (zh) 一种zl205a铝合金的强韧化处理工艺
CN114381641B (zh) 一种新型高强塑性低稀土含量Mg-Al-Zn-RE合金及其制备方法
CN111218590B (zh) 一种高强度高成型性铝镁铜合金板材及其制备方法
US20180142336A1 (en) Alloys for highly shaped aluminum products and methods of making the same
CN112030077A (zh) 一种含锰高强低密度钢及其制备方法和应用
CN112375949A (zh) 一种车体用高强7系铝合金薄板的热处理工艺
CN113308653B (zh) 一种基于喷射成形的铝锂合金热处理制备方法
CN114101556B (zh) 一种短流程制备tb8钛合金薄板的加工方法
CN111041311A (zh) 一种具有低成本高性能稀土镁合金及制备技术
CN112337972A (zh) 二次变形制备高性能镁合金的方法
CN114540649A (zh) 高成形耐烘烤5xxx系铝合金板材及其制备方法
CN111876700B (zh) 一种粉末冶金铝合金冷轧板材的热处理工艺
CN112281093A (zh) 一种高性能镁锂合金薄带的制备工艺
CN109988947A (zh) 耐蚀、可焊的合金及其制备方法
CN116727443A (zh) 一种镍基合金卷板及其生产方法
CN110541131A (zh) 一种基于粒子激发形核的Al-Cu-Li合金形变热处理工艺
CN113862538B (zh) 高强耐热镁合金薄板及其制备方法
CN115386818A (zh) 一种Al-Cu-Li系合金热轧板坯的形变热处理方法
CN109321843B (zh) 一种高强度高塑性冷轧钢板及其制造方法
CN115074582B (zh) 一种具有双峰晶粒组织的亚共晶Al-Ce合金的制备方法
CN114959488B (zh) 一种工业纯铁中厚板及其生产方法

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 19858167

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 19858167

Country of ref document: EP

Kind code of ref document: A1

32PN Ep: public notification in the ep bulletin as address of the adressee cannot be established

Free format text: NOTING OF LOSS OF RIGHTS PURSUANT TO RULE 112(1) EPC