A Differential Hot Forming Method for Preparation of High Strength and Toughness Magnesium Alloy

A magnesium alloy and differential heat technology, applied in the field of magnesium alloy materials and their deformation processing, can solve the problems of rare earth elements increasing the cost of alloy preparation and unfavorable wide application of alloys, so as to improve the efficiency of alloy preparation, precisely control the microstructure, and improve the quality of alloys. performance effect

Active Publication Date: 2022-05-27
LANZHOU UNIVERSITY OF TECHNOLOGY
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the common problem is that adding more rare earth elements increases the cost of alloy preparation, which is not conducive to the wide application of alloys in industrial production.

Method used

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  • A Differential Hot Forming Method for Preparation of High Strength and Toughness Magnesium Alloy

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0047] Example 1: Take the equal channel corner extrusion deformation as an example, the specific steps are as follows:

[0048] (1) Ingredients: The alloy raw materials are high-purity magnesium ingots (99.95%), high-purity zinc ingots (99.995%, 50 mm), high-purity tin particles (99.99%, Φ2×5 mm), and Mg-30 wt.% Zr master alloy. First, weigh the original material slightly higher than the alloy composition, and then polish its surface oxide film (except for high-purity tin particles) to a clean and non-oxidized surface and the same quality as the composition (error less than 0.01 g), and finally clean the original material , dry for use;

[0049] (2) Preheating: Preheat dried magnesium ingots, high-purity tin particles, zinc ingots and Mg-30 wt.% Zr master alloy at 200-250 °C for 30-35 min. In addition, the stainless steel crucible and the stainless steel casting mold for smelting are all preheated and kept at this temperature for standby use;

[0050] (3) Smelting and casti...

Embodiment 2

[0054] Embodiment 2: In this embodiment, steps (1), (2), (3), (4) are the same as those in Embodiment 1.

[0055] The difference between this example and Example 1 is that the alloy obtained in step (4) is subjected to four-pass differential thermal iso-channel corner extrusion deformation. At room temperature, the alloy sample and the equal-channel corner extrusion die were coated with high-purity graphite mixed with a small amount of synthetic oil at the same time, and then only the extrusion die was heated to 300 °C, and the alloy sample was not heated. When the temperature was stable, the temperature was kept for 30 min; after the heat preservation, the room temperature alloy sample was put into the mold for four passes of extrusion deformation. The extrusion speed is 12 mm / s, the channel turning angle is 120°, and the deformation path is the Bc path. After the extrusion was completed, the sample was air-cooled to room temperature to obtain a four-pass deformed alloy. Th...

Embodiment 3

[0056] Embodiment 3: In this implementation, steps (1), (2), (3) are the same as those in Embodiment 1.

[0057] The difference from Example 1 is:

[0058] (4) Heat treatment: The as-cast alloy obtained by (3) is subjected to heat treatment, including solution heat treatment and aging heat treatment. The solution heat treatment process is to keep the as-cast alloy at 400 °C for 12 h, and then put the sample into 25 °C clean water for quenching to obtain a solid solution (T4) alloy; the aging heat treatment process is to heat the solid solution alloy at 300 °C. Heat-treated (T6) alloy was obtained by holding at ℃ for 10 h, and then air-cooled to room temperature;

[0059] (5) Extrusion: The heat-treated (T6) alloy (h=10-15 mm, d=40 mm) obtained in (4) was subjected to positive extrusion. At room temperature, the positive extrusion die was coated with high-purity graphite mixed with a small amount of synthetic oil, and heated to 300 °C. After the temperature was stabilized, th...

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Abstract

The invention discloses a differential thermal forming method for preparing high-strength and toughness magnesium alloys, the purpose of which is to only heat the forming mold at the deformation temperature without heating the alloy sample. After holding for a certain time, the alloy billet at room temperature is put into a heated forming mold to achieve stable deformation. The steps are: step (1) batching; step (2) preheating: preheating the dried magnesium ingot, tin particles, zinc block and Mg-Zr master alloy at 200-250°C for 30-35 min; step (3) Melting and casting to obtain the cast alloy; step (4) heat treatment, including solution treatment and aging treatment; steps (5), (6) extrusion forming; steps (7), (8) differential thermal equal channel angular extrusion take shape. With this forming method as the core, stable forming by differential heat equal channel angular extrusion has been successfully realized. The tensile strength of the alloy is more than 300 MPa, and the elongation is close to 30%. It has excellent comprehensive mechanical properties and a good match between strength and plasticity.

Description

technical field [0001] The invention relates to the field of magnesium alloy materials and their deformation processing, in particular to the differential hot forming technology of high-strength and tough magnesium alloys. Background technique [0002] Due to the special crystal structure and limited deformation mechanism of magnesium and magnesium alloys, it is difficult to process and form at room temperature, and the performance optimization is insufficient, which has become a bottleneck problem that restricts its industrial application. [0003] Magnesium belongs to the close-packed hexagonal structure, and it is easy to form a strong basal texture during the plastic deformation process. This is the main reason that restricts the room temperature forming of magnesium alloys. When the basal texture is formed, with the change of the applied stress direction, the slip system of each dislocation in the alloy cannot effectively adapt to the plastic strain, resulting in defor...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B21C29/04B21C23/04C22C23/00C22C1/03C22F1/06
CPCB21C23/002B21C29/04B21C23/04C22C23/00C22C1/03C22F1/002C22F1/06
Inventor 刘德学周田水王炳张全发郭菲菲张国锋
Owner LANZHOU UNIVERSITY OF TECHNOLOGY
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