5.25% Convertible Notes due 2014

Exhibit 4.1

UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION (“DTC”), NEW YORK, NEW YORK, TO THE COMPANY OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE TO CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

TRANSFERS OF THIS GLOBAL NOTE SHALL BE LIMITED TO TRANSFERS IN WHOLE, BUT NOT IN PART, TO NOMINEES OF DTC OR TO A SUCCESSOR THEREOF OR SUCH SUCCESSOR’S NOMINEE AND TRANSFERS OF PORTIONS OF THIS GLOBAL NOTE SHALL BE LIMITED TO TRANSFERS MADE IN ACCORDANCE WITH THE RESTRICTIONS SET FORTH IN THE THIRD SUPPLEMENTAL INDENTURE AND THE ORIGINAL INDENTURE.

This Note is a Book-Entry Note within the meaning of the Original Indenture and every Note authenticated and delivered upon registration of transfer of, or in exchange for or in lieu of, this Note shall be a Book-Entry Note except in the limited circumstances described in the Original Indenture.

5.25% Convertible Notes due 2014

Alcoa Inc., a corporation duly organized and existing under the laws of Pennsylvania (herein called the “Company”, which term includes any successor Person under the Third Supplemental Indenture referred to on the reverse hereof), for value received, hereby promises to pay to Cede & Co., or registered assigns, the principal sum of             Million (United States) Dollars (US$            ), as revised by the Schedule of Increases and Decreases in Global Note attached hereto, on March 15, 2014, and to pay interest thereon from March 24, 2009, or from the most recent March 15 or September 15 (each, an “Interest Payment Date”) to which interest has been paid, deemed paid or duly provided for, semi-annually in arrears on March 15 and September 15 in each year, commencing September 15, 2009, at the rate of 5.25% per annum, until the principal hereof is converted into shares of common stock of the Company, paid, deemed paid or made available for payment.

The interest so payable, and punctually paid or duly provided for, on any Interest Payment Date will, as provided in such Third Supplemental Indenture, be paid to the Person in whose name this Note (or one or more Predecessor Securities) is registered at the close of business on the Regular Record Date for such interest, which shall be the March 1 or September 1 (whether or not a Business Day), as the case may be, next preceding such Interest Payment Date. Interest will be paid on the basis of a 360-day year consisting of twelve 30-day months. Except as otherwise provided in the Third Supplemental Indenture, any such interest not so punctually paid or duly provided for will forthwith cease to be payable to the Holder on such Regular Record Date and may either be paid to the Person in whose name this Note (or one or more Predecessor Securities) is registered at the close of business on a Special Record Date for the payment of such Defaulted Interest to be fixed by the Trustee, notice whereof shall be given to Holders of

Notes of this series not less than 10 days prior to such Special Record Date, or be paid at any time in any other lawful manner not inconsistent with the requirements of any securities exchange on which the Notes of this series may be listed, and upon such notice as may be required by such exchange, all as more fully provided in said Third Supplemental Indenture. Payment of the principal of and any premium and interest on this Note will be made (a) at the Corporate Trust Office of the Trustee in Pittsburgh, Pennsylvania, or such other office or agency of the Company as may be designated by it for such purpose in the Borough of Manhattan, The City of New York, in such coin or currency of the United States of America as at the time of payment shall be legal tender for the payment of public and private debts or (b) subject to any laws or regulations applicable thereto and to the right of the Company (limited as provided in the Third Supplemental Indenture) to rescind the designation of any such Paying Agent, at the main offices of the Company in Pittsburgh, Pennsylvania, or at such other offices or agencies as the Company may designate, by United States dollar check drawn on, or transfer to a United States dollar account maintained by the payee with, a bank in The City of New York; provided, however, that at the option of the Company payment of interest may be made by United States dollar check mailed to the address of the Person entitled thereto as such address shall appear in the Security Register.

Reference is hereby made to the further provisions of this Note set forth on the reverse hereof, which further provisions shall for all purposes have the same effect as if set forth at this place.

Unless the certificate of authentication hereon has been executed by the Trustee referred to on the reverse hereof, directly or through an Authenticating Agent, by manual signature of an authorized signatory, this Note shall not be entitled to any benefit under the Original Indenture or be valid or obligatory for any purpose.

IN WITNESS WHEREOF, the Company has caused this instrument to be duly executed under its corporate seal.

Dated: March 24, 2009

[SEAL]

CERTIFICATE OF AUTHENTICATION

This is one of the Notes of the series designated

therein referred to in the within-mentioned Third

Supplemental Indenture and the Original

Indenture.

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This Note is one of a duly authorized issue of securities of the Company (herein called the “ Notes ”), issued under a Third Supplemental Indenture dated as of March 24, 2009 (the “ Third Supplemental Indenture ”) to an indenture dated as of September 30, 1993, as supplemented by a First Supplemental Indenture dated as of January 25, 2007 and a Second Supplemental Indenture dated as of July 15, 2008 (as it may be further amended or supplemented from time to time in accordance with the terms thereof, the “ Original Indenture ”), between the Company and The Bank of New York Mellon Trust Company, N.A., as successor in interest to J. P. Morgan Trust Company, National Association (formerly Chase Manhattan Trust Company, National Association, as successor trustee to PNC Bank, National Association), as Trustee (herein called the “ Trustee ”, which term includes any successor trustee under the Original Indenture), to which the Third Supplemental Indenture, the Original Indenture and all indentures supplemental thereto reference is hereby made for a statement of the respective rights, limitations of rights, obligations duties and immunities thereunder of the Company, the Trustee and the Holders of the Notes and of the terms upon which the Notes are, and are to be, authenticated and delivered. This Note is one of the series designated on the face hereof, initially issued in the aggregate principal amount of (U.S.) $575,000,000.

No reference herein to the Third Supplemental Indenture and the Original Indenture, and no provision of this Note or of the Third Supplemental Indenture or the Original Indenture, shall alter or impair the obligation of the Company, which is absolute and unconditional, to pay the principal of (and premium, if any) and interest on this Note at the times, place(s) and rate, and in the coin or currency, herein prescribed. In the event of any conflict or inconsistency between the terms and provisions of this Note and the terms and provisions of the Third Supplemental Indenture and the Original Indenture, the terms and provisions of the Third Supplemental Indenture and the Original Indenture shall control. Capitalized terms used but not defined herein shall have the meanings assigned to them in the Third Supplemental Indenture and the Original Indenture.

The Notes of this series are not subject to redemption at the election of the Company.

If any Interest Payment Date falls on a day that is not a Business Day, such Interest Payment Date shall be postponed to the next succeeding Business Day and no interest on such payment will accrue for the period from the Interest Payment Date to such next succeeding Business Day. If the Stated Maturity date would fall on a day that is not a Business Day, the required payment of interest, if any, and principal (and Additional Interest, if any), will be made on the next succeeding Business Day and no interest on such payment will accrue for the period from and after the Stated Maturity date to such next succeeding Business Day. If a Fundamental Change Purchase Date would fall on a day that is not a Business Day, the Company will purchase the Notes tendered for purchase on the next succeeding Business Day and no interest or Additional Interest on such Notes will accrue for the period from and after the earlier Fundamental Change Purchase Date to such next succeeding Business Day. The Company will pay the Fundamental Change Purchase Price promptly following the later of (i) such next succeeding Business Day or (ii) the time of book entry transfer or the delivery of the Note.

The Holder of this Note after 5:00 p.m., New York City time, on a Regular Record Date shall be entitled to receive interest (including any Additional Interest), on this Note on the corresponding Interest Payment Date. Holders of this Note at 5:00 p.m., New York City time, on a Regular Record Date will receive payment of interest (including any Additional Interest) payable on the corresponding Interest Payment Date notwithstanding the conversion of this Note at any time after 5:00 p.m., New York City time on such Regular Record Date. If this Note is surrendered for conversion during the period after 5:00 p.m., New York City time, on any Regular Record Date to 9:00 a.m., New York City time, on the corresponding Interest Payment Date it must be accompanied by payment of an amount equal to the interest (including any Additional Interest) that the Holder is to receive on this Note on such Interest Payment Date.

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Notwithstanding the foregoing, no such payment of interest (including any Additional Interest) need be made by the converting Holder (i) for conversions following the Regular Record Date immediately preceding the Stated Maturity, (ii) if the Company has specified a Fundamental Change Purchase Date that is after a Regular Record Date and on or prior to the corresponding Interest Payment Date, or (iii) to the extent of any overdue interest (including any overdue Additional Interest) existing at the time of conversion of this Note. Except where this Note surrendered for conversion must be accompanied by payment as described above, no interest or Additional Interest on converted portions of this Note will be payable by the Company on an